Chapter 6

  1. In this exercise, we will predict the number of applications received using the other variables in the College data set.
  1. Split the data set into a training set and a test set.
data <- College
set.seed(15495)
iTrain <- createDataPartition(y = College$Apps, p = 0.75, list = FALSE)
Train <- data[iTrain, ]
Test <- data[-iTrain, ]
  1. Graph

The application to private university is low compared to public university. But, this might come from the fact that the number of private university in the sample is low compared to public.

qplot(x = Private, y = log(Apps+1), data = Train, geom = "boxplot",
            main = "Application per Private status")

But, given the table, private college in the sample is significantly high than non-private ones, counting 421.

table(Train$Private)
## 
##  No Yes 
## 163 422
  1. Fit a linear model using least squares on the training set, and report the test error obtained.
set.seed(13587)
ctrl <- trainControl(method = "repeatedcv", number = 10)
fit.lin <- train(Apps ~. , data = Train, trControl = ctrl, method = "lmStepAIC" )
## Start:  AIC=7323.86
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    179266  547505047 7322.0
## - Personal     1    298768  547624549 7322.2
## - Terminal     1    388306  547714087 7322.2
## - P.Undergrad  1   1473678  548799459 7323.3
## - perc.alumni  1   1900094  549225875 7323.7
## - PhD          1   1934977  549260758 7323.7
## <none>                      547325781 7323.9
## - S.F.Ratio    1   3077936  550403718 7324.8
## - Outstate     1   5230917  552556699 7326.9
## - Top25perc    1   7182685  554508466 7328.7
## - Enroll       1   7531883  554857664 7329.1
## - F.Undergrad  1   8180795  555506576 7329.7
## - PrivateYes   1   9854403  557180184 7331.2
## - Grad.Rate    1  10396357  557722138 7331.8
## - Room.Board   1  11889094  559214875 7333.2
## - Expend       1  24494444  571820226 7344.9
## - Top10perc    1  52454155  599779937 7370.0
## - Accept       1 484103728 1031429509 7655.2
## 
## Step:  AIC=7322.04
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Personal + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    348181  547853228 7320.4
## - Personal     1    395139  547900186 7320.4
## - P.Undergrad  1   1522177  549027224 7321.5
## - perc.alumni  1   2002113  549507160 7322.0
## - PhD          1   2007124  549512171 7322.0
## <none>                      547505047 7322.0
## - S.F.Ratio    1   3069514  550574561 7323.0
## - Outstate     1   5356621  552861668 7325.2
## - Top25perc    1   7185420  554690467 7326.9
## - Enroll       1   7591842  555096889 7327.3
## - F.Undergrad  1   8162473  555667521 7327.8
## - PrivateYes   1   9767857  557272904 7329.3
## - Grad.Rate    1  10472613  557977661 7330.0
## - Room.Board   1  12229472  559734519 7331.7
## - Expend       1  24663954  572169002 7343.2
## - Top10perc    1  52819935  600324982 7368.5
## - Accept       1 486013729 1033518776 7654.2
## 
## Step:  AIC=7320.37
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Personal + 
##     PhD + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1    378212  548231440 7318.7
## - P.Undergrad  1   1530796  549384025 7319.8
## <none>                      547853228 7320.4
## - perc.alumni  1   2154172  550007401 7320.4
## - S.F.Ratio    1   3170297  551023525 7321.4
## - Outstate     1   5730243  553583471 7323.8
## - Top25perc    1   7538864  555392092 7325.6
## - Enroll       1   7545437  555398666 7325.6
## - PhD          1   7570127  555423355 7325.6
## - F.Undergrad  1   7961255  555814483 7326.0
## - PrivateYes   1   9481218  557334447 7327.4
## - Grad.Rate    1  10582853  558436082 7328.4
## - Room.Board   1  11912066  559765295 7329.7
## - Expend       1  24425839  572279067 7341.3
## - Top10perc    1  54045176  601898405 7367.9
## - Accept       1 487429980 1035283209 7653.1
## 
## Step:  AIC=7318.73
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - P.Undergrad  1   1754029  549985469 7318.4
## <none>                      548231440 7318.7
## - perc.alumni  1   2445129  550676570 7319.1
## - S.F.Ratio    1   3066579  551298020 7319.7
## - Outstate     1   5908184  554139624 7322.4
## - Enroll       1   7443471  555674911 7323.8
## - Top25perc    1   7499711  555731151 7323.9
## - PhD          1   7589604  555821044 7324.0
## - F.Undergrad  1   8481410  556712850 7324.8
## - PrivateYes   1   9649188  557880629 7325.9
## - Grad.Rate    1  10337468  558568908 7326.6
## - Room.Board   1  11751496  559982936 7327.9
## - Expend       1  24785342  573016782 7340.0
## - Top10perc    1  54082735  602314176 7366.2
## - Accept       1 493920080 1042151520 7654.6
## 
## Step:  AIC=7318.41
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + Outstate + Room.Board + PhD + S.F.Ratio + perc.alumni + 
##     Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      549985469 7318.4
## - perc.alumni  1   2552045  552537514 7318.8
## - S.F.Ratio    1   2944150  552929619 7319.2
## - Outstate     1   5997082  555982551 7322.1
## - PhD          1   6893802  556879271 7323.0
## - Top25perc    1   7434518  557419987 7323.5
## - Enroll       1   7678943  557664412 7323.7
## - Grad.Rate    1   9380862  559366331 7325.3
## - PrivateYes   1   9992465  559977934 7325.9
## - F.Undergrad  1  11627915  561613383 7327.4
## - Room.Board   1  12256255  562241724 7328.0
## - Expend       1  25860385  575845854 7340.6
## - Top10perc    1  52733116  602718585 7364.6
## - Accept       1 494693684 1044679153 7653.9
## Start:  AIC=7362.46
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1      3817  574726923 7360.5
## - Terminal     1    103151  574826257 7360.6
## - Books        1    236234  574959340 7360.7
## - perc.alumni  1   1347064  576070169 7361.7
## - P.Undergrad  1   1734428  576457534 7362.0
## <none>                      574723106 7362.5
## - PhD          1   2309734  577032840 7362.6
## - S.F.Ratio    1   2731198  577454304 7363.0
## - Enroll       1   5349364  580072470 7365.3
## - Outstate     1   6288022  581011128 7366.2
## - Grad.Rate    1   6734972  581458078 7366.6
## - F.Undergrad  1   7253798  581976904 7367.1
## - Top25perc    1   9719831  584442937 7369.3
## - PrivateYes   1  13207871  587930977 7372.4
## - Room.Board   1  14818941  589542047 7373.9
## - Expend       1  26520901  601244006 7384.2
## - Top10perc    1  62701336  637424442 7415.0
## - Accept       1 496058019 1070781125 7688.4
## 
## Step:  AIC=7360.46
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    103075  574829998 7358.6
## - Books        1    232493  574959416 7358.7
## - perc.alumni  1   1355173  576082096 7359.7
## - P.Undergrad  1   1752425  576479348 7360.1
## <none>                      574726923 7360.5
## - PhD          1   2313869  577040792 7360.6
## - S.F.Ratio    1   2782525  577509448 7361.0
## - Enroll       1   5358082  580085005 7363.4
## - Outstate     1   6295889  581022812 7364.2
## - Grad.Rate    1   6808399  581535322 7364.7
## - F.Undergrad  1   7268390  581995313 7365.1
## - Top25perc    1   9718724  584445647 7367.3
## - PrivateYes   1  13205954  587932877 7370.4
## - Room.Board   1  14917835  589644758 7372.0
## - Expend       1  26546371  601273295 7382.3
## - Top10perc    1  62708467  637435391 7413.0
## - Accept       1 499912537 1074639460 7688.3
## 
## Step:  AIC=7358.56
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    218339  575048338 7356.8
## - perc.alumni  1   1468769  576298768 7357.9
## - P.Undergrad  1   1743006  576573004 7358.2
## <none>                      574829998 7358.6
## - S.F.Ratio    1   2821113  577651111 7359.1
## - Enroll       1   5297207  580127205 7361.4
## - Outstate     1   6481989  581311987 7362.5
## - PhD          1   6948297  581778295 7362.9
## - Grad.Rate    1   7013194  581843192 7362.9
## - F.Undergrad  1   7182873  582012871 7363.1
## - Top25perc    1  10012757  584842755 7365.7
## - PrivateYes   1  13102878  587932877 7368.4
## - Room.Board   1  14850772  589680770 7370.0
## - Expend       1  26453149  601283148 7380.3
## - Top10perc    1  63613806  638443805 7411.9
## - Accept       1 499882003 1074712002 7686.3
## 
## Step:  AIC=7356.76
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - perc.alumni  1   1513313  576561650 7356.1
## - P.Undergrad  1   1833438  576881775 7356.4
## <none>                      575048338 7356.8
## - S.F.Ratio    1   2792727  577841064 7357.3
## - Enroll       1   5285735  580334073 7359.6
## - Outstate     1   6642418  581690755 7360.8
## - PhD          1   6949912  581998249 7361.1
## - Grad.Rate    1   6968633  582016970 7361.1
## - F.Undergrad  1   7223598  582271936 7361.3
## - Top25perc    1   9977917  585026255 7363.8
## - PrivateYes   1  13064603  588112940 7366.6
## - Room.Board   1  15293307  590341644 7368.6
## - Expend       1  26796468  601844806 7378.8
## - Top10perc    1  64129471  639177809 7410.5
## - Accept       1 499672300 1074720637 7684.3
## 
## Step:  AIC=7356.14
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - P.Undergrad  1   1963984  578525635 7355.9
## <none>                      576561650 7356.1
## - S.F.Ratio    1   3190158  579751808 7357.0
## - Grad.Rate    1   5788485  582350136 7359.4
## - Enroll       1   6284929  582846579 7359.9
## - F.Undergrad  1   7382478  583944129 7360.8
## - PhD          1   7443634  584005284 7360.9
## - Outstate     1   9220074  585781724 7362.5
## - Top25perc    1  10665471  587227122 7363.8
## - PrivateYes   1  13610130  590171781 7366.4
## - Room.Board   1  16966909  593528560 7369.4
## - Expend       1  26660086  603221736 7378.0
## - Top10perc    1  64235137  640796787 7409.8
## - Accept       1 545338693 1121900343 7705.0
## 
## Step:  AIC=7355.93
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + Outstate + Room.Board + PhD + S.F.Ratio + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      578525635 7355.9
## - S.F.Ratio    1   2951857  581477492 7356.6
## - Grad.Rate    1   4829160  583354795 7358.3
## - Enroll       1   6191397  584717031 7359.5
## - PhD          1   6707840  585233475 7360.0
## - F.Undergrad  1   9353102  587878737 7362.4
## - Outstate     1   9389734  587915369 7362.4
## - Top25perc    1  10567831  589093465 7363.5
## - PrivateYes   1  14409087  592934722 7366.9
## - Room.Board   1  18291283  596816917 7370.3
## - Expend       1  27413402  605939036 7378.3
## - Top10perc    1  62598600  641124235 7408.1
## - Accept       1 544099403 1122625037 7703.3
## Start:  AIC=7348.82
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1      8996  560051940 7346.8
## - Books        1    234297  560277242 7347.0
## - Terminal     1    497976  560540920 7347.3
## - perc.alumni  1   1315799  561358744 7348.1
## <none>                      560042945 7348.8
## - P.Undergrad  1   2438819  562481763 7349.1
## - PhD          1   2963338  563006283 7349.6
## - S.F.Ratio    1   3326648  563369593 7349.9
## - Enroll       1   5456341  565499285 7351.9
## - Outstate     1   5567326  565610270 7352.0
## - F.Undergrad  1   7310198  567353142 7353.7
## - Top25perc    1   7526573  567569517 7353.9
## - Grad.Rate    1   8523356  568566301 7354.8
## - Room.Board   1  12677821  572720765 7358.6
## - PrivateYes   1  15117758  575160702 7360.9
## - Expend       1  27734340  587777285 7372.3
## - Top10perc    1  58775682  618818626 7399.4
## - Accept       1 519744633 1079787577 7692.8
## 
## Step:  AIC=7346.83
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    226413  560278353 7345.0
## - Terminal     1    498628  560550568 7345.3
## - perc.alumni  1   1309161  561361101 7346.1
## <none>                      560051940 7346.8
## - P.Undergrad  1   2457606  562509547 7347.1
## - PhD          1   2967988  563019928 7347.6
## - S.F.Ratio    1   3384079  563436019 7348.0
## - Enroll       1   5465101  565517042 7349.9
## - Outstate     1   5568357  565620297 7350.0
## - F.Undergrad  1   7311279  567363219 7351.7
## - Top25perc    1   7521736  567573676 7351.9
## - Grad.Rate    1   8587402  568639342 7352.9
## - Room.Board   1  12832000  572883940 7356.8
## - PrivateYes   1  15110337  575162277 7358.9
## - Expend       1  27786298  587838238 7370.3
## - Top10perc    1  58766916  618818856 7397.4
## - Accept       1 523505618 1083557558 7692.6
## 
## Step:  AIC=7345.04
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    459128  560737481 7343.5
## - perc.alumni  1   1386875  561665229 7344.3
## <none>                      560278353 7345.0
## - P.Undergrad  1   2572772  562851125 7345.5
## - PhD          1   3043906  563322260 7345.9
## - S.F.Ratio    1   3439722  563718075 7346.3
## - Enroll       1   5437551  565715905 7348.1
## - Outstate     1   5816346  566094699 7348.5
## - F.Undergrad  1   7307529  567585882 7349.9
## - Top25perc    1   7485225  567763578 7350.0
## - Grad.Rate    1   8604856  568883209 7351.1
## - Room.Board   1  13251030  573529384 7355.4
## - PrivateYes   1  14968852  575247205 7356.9
## - Expend       1  28280068  588558422 7369.0
## - Top10perc    1  59234006  619512360 7396.0
## - Accept       1 523306135 1083584488 7690.7
## 
## Step:  AIC=7343.48
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - perc.alumni  1   1540268  562277749 7342.9
## <none>                      560737481 7343.5
## - P.Undergrad  1   2566271  563303752 7343.9
## - S.F.Ratio    1   3528795  564266276 7344.8
## - Enroll       1   5324648  566062129 7346.5
## - Outstate     1   6152976  566890457 7347.2
## - F.Undergrad  1   7099315  567836796 7348.1
## - Top25perc    1   7897779  568635261 7348.8
## - Grad.Rate    1   8822017  569559498 7349.7
## - PhD          1  10816042  571553523 7351.5
## - Room.Board   1  12856696  573594177 7353.4
## - PrivateYes   1  14582881  575320362 7355.0
## - Expend       1  27963258  588700739 7367.1
## - Top10perc    1  60615147  621352628 7395.6
## - Accept       1 523177980 1083915461 7688.8
## 
## Step:  AIC=7342.92
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      562277749 7342.9
## - P.Undergrad  1   2587409  564865159 7343.3
## - S.F.Ratio    1   4011330  566289080 7344.7
## - Enroll       1   6404889  568682638 7346.9
## - F.Undergrad  1   7363496  569641246 7347.8
## - Grad.Rate    1   7501127  569778877 7347.9
## - Outstate     1   8280960  570558710 7348.6
## - Top25perc    1   8467145  570744894 7348.8
## - PhD          1  11540609  573818358 7351.6
## - Room.Board   1  14551472  576829221 7354.4
## - PrivateYes   1  15489881  577767630 7355.2
## - Expend       1  27968557  590246306 7366.5
## - Top10perc    1  60651318  622929068 7394.9
## - Accept       1 570691352 1132969101 7710.1
## Start:  AIC=7313.3
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1       713  536448143 7311.3
## - Personal     1      5073  536452504 7311.3
## - F.Undergrad  1    231500  536678931 7311.5
## - Terminal     1    309793  536757223 7311.6
## - Enroll       1    696267  537143698 7312.0
## - perc.alumni  1    855115  537302546 7312.1
## - PhD          1   2031211  538478641 7313.3
## <none>                      536447431 7313.3
## - P.Undergrad  1   2074519  538521950 7313.3
## - S.F.Ratio    1   2605234  539052665 7313.9
## - Outstate     1   8184369  544631799 7319.3
## - Grad.Rate    1   9320010  545767441 7320.4
## - Top25perc    1  14615115  551062546 7325.4
## - PrivateYes   1  15612154  552059585 7326.4
## - Room.Board   1  17182738  553630168 7327.9
## - Expend       1  26719076  563166506 7336.9
## - Top10perc    1  69179486  605626917 7375.1
## - Accept       1 492814551 1029261981 7654.1
## 
## Step:  AIC=7311.3
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Personal + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1      4598  536452742 7309.3
## - F.Undergrad  1    231200  536679344 7309.5
## - Terminal     1    311277  536759420 7309.6
## - Enroll       1    696304  537144447 7310.0
## - perc.alumni  1    854592  537302736 7310.1
## - PhD          1   2033288  538481432 7311.3
## <none>                      536448143 7311.3
## - P.Undergrad  1   2073809  538521953 7311.3
## - S.F.Ratio    1   2605580  539053724 7311.9
## - Outstate     1   8233172  544681315 7317.3
## - Grad.Rate    1   9319841  545767984 7318.4
## - Top25perc    1  14628421  551076565 7323.5
## - PrivateYes   1  15651123  552099266 7324.4
## - Room.Board   1  17368320  553816463 7326.1
## - Expend       1  26746604  563194747 7334.9
## - Top10perc    1  69229772  605677915 7373.1
## - Accept       1 492912150 1029360293 7652.1
## 
## Step:  AIC=7309.31
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - F.Undergrad  1    237920  536690662 7307.5
## - Terminal     1    308151  536760893 7307.6
## - Enroll       1    693081  537145823 7308.0
## - perc.alumni  1    895693  537348435 7308.2
## <none>                      536452742 7309.3
## - PhD          1   2043871  538496612 7309.3
## - P.Undergrad  1   2141489  538594230 7309.4
## - S.F.Ratio    1   2607294  539060036 7309.9
## - Outstate     1   8310684  544763426 7315.4
## - Grad.Rate    1   9326177  545778919 7316.4
## - Top25perc    1  14630686  551083428 7321.5
## - PrivateYes   1  15649956  552102698 7322.4
## - Room.Board   1  17392851  553845593 7324.1
## - Expend       1  26894646  563347388 7333.0
## - Top10perc    1  69236254  605688996 7371.2
## - Accept       1 499588060 1036040802 7653.5
## 
## Step:  AIC=7307.54
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     P.Undergrad + Outstate + Room.Board + PhD + Terminal + S.F.Ratio + 
##     perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    286690  536977351 7305.8
## - Enroll       1    502997  537193659 7306.0
## - perc.alumni  1    923235  537613897 7306.4
## - PhD          1   2032295  538722957 7307.5
## <none>                      536690662 7307.5
## - P.Undergrad  1   2698700  539389362 7308.2
## - S.F.Ratio    1   2700215  539390877 7308.2
## - Outstate     1   8845859  545536520 7314.1
## - Grad.Rate    1   9230387  545921049 7314.5
## - Top25perc    1  14691226  551381888 7319.7
## - PrivateYes   1  16203292  552893954 7321.2
## - Room.Board   1  17503058  554193719 7322.4
## - Expend       1  26847562  563538223 7331.2
## - Top10perc    1  70209972  606900634 7370.2
## - Accept       1 500422365 1037113027 7652.1
## 
## Step:  AIC=7305.82
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     P.Undergrad + Outstate + Room.Board + PhD + S.F.Ratio + perc.alumni + 
##     Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Enroll       1    508394  537485746 7304.3
## - perc.alumni  1   1007873  537985224 7304.8
## <none>                      536977351 7305.8
## - P.Undergrad  1   2668520  539645872 7306.4
## - S.F.Ratio    1   2789079  539766430 7306.5
## - PhD          1   7757872  544735223 7311.4
## - Outstate     1   9153731  546131083 7312.7
## - Grad.Rate    1   9492289  546469640 7313.0
## - Top25perc    1  15097185  552074536 7318.4
## - PrivateYes   1  15924158  552901509 7319.2
## - Room.Board   1  17223045  554200396 7320.4
## - Expend       1  26816708  563794060 7329.5
## - Top10perc    1  70833530  607810881 7369.0
## - Accept       1 500218219 1037195570 7650.1
## 
## Step:  AIC=7304.32
## .outcome ~ PrivateYes + Accept + Top10perc + Top25perc + P.Undergrad + 
##     Outstate + Room.Board + PhD + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df  Sum of Sq        RSS    AIC
## - perc.alumni  1    1324004  538809749 7303.6
## <none>                       537485746 7304.3
## - P.Undergrad  1    2329220  539814965 7304.6
## - S.F.Ratio    1    2629662  540115407 7304.9
## - PhD          1    7779569  545265314 7309.9
## - Outstate     1    8667873  546153619 7310.7
## - Grad.Rate    1    9936155  547421900 7312.0
## - Top25perc    1   14776216  552261962 7316.6
## - PrivateYes   1   15521101  553006846 7317.3
## - Room.Board   1   18510542  555996287 7320.1
## - Expend       1   26972246  564457991 7328.1
## - Top10perc    1   71199812  608685558 7367.8
## - Accept       1 2681094775 3218580521 8243.8
## 
## Step:  AIC=7303.61
## .outcome ~ PrivateYes + Accept + Top10perc + Top25perc + P.Undergrad + 
##     Outstate + Room.Board + PhD + S.F.Ratio + Expend + Grad.Rate
## 
##               Df  Sum of Sq        RSS    AIC
## <none>                       538809749 7303.6
## - P.Undergrad  1    2307290  541117039 7303.9
## - S.F.Ratio    1    2910225  541719974 7304.4
## - PhD          1    8183150  546992900 7309.5
## - Grad.Rate    1    8823936  547633685 7310.2
## - Outstate     1   11177051  549986800 7312.4
## - Top25perc    1   15288736  554098486 7316.3
## - PrivateYes   1   16233179  555042929 7317.2
## - Room.Board   1   21273002  560082752 7322.0
## - Expend       1   26800551  565610300 7327.1
## - Top10perc    1   70525333  609335082 7366.3
## - Accept       1 2769028788 3307838537 8256.1
## Start:  AIC=7335.88
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1       977  546452524 7333.9
## - Books        1     54924  546506472 7333.9
## - Terminal     1    453574  546905122 7334.3
## - S.F.Ratio    1    941816  547393364 7334.8
## - Enroll       1   1495241  547946788 7335.3
## <none>                      546451548 7335.9
## - P.Undergrad  1   2234591  548686139 7336.0
## - PhD          1   2487449  548938997 7336.3
## - Outstate     1   2790785  549242333 7336.6
## - perc.alumni  1   2986016  549437564 7336.7
## - F.Undergrad  1   3945722  550397270 7337.7
## - Grad.Rate    1   7943907  554395454 7341.5
## - PrivateYes   1   9671616  556123164 7343.1
## - Top25perc    1   9941311  556392859 7343.4
## - Room.Board   1  12533133  558984681 7345.8
## - Expend       1  23102309  569553857 7355.7
## - Top10perc    1  64211538  610663086 7392.4
## - Accept       1 526036771 1072488319 7689.2
## 
## Step:  AIC=7333.88
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1     58578  546511102 7331.9
## - Terminal     1    452630  546905154 7332.3
## - S.F.Ratio    1    945596  547398120 7332.8
## - Enroll       1   1494388  547946913 7333.3
## <none>                      546452524 7333.9
## - P.Undergrad  1   2288235  548740759 7334.1
## - PhD          1   2489623  548942148 7334.3
## - Outstate     1   2811140  549263664 7334.6
## - perc.alumni  1   3067222  549519746 7334.8
## - F.Undergrad  1   3977727  550430251 7335.7
## - Grad.Rate    1   7953063  554405587 7339.5
## - PrivateYes   1   9677140  556129664 7341.1
## - Top25perc    1   9944548  556397072 7341.4
## - Room.Board   1  12617933  559070457 7343.9
## - Expend       1  23175133  569627658 7353.8
## - Top10perc    1  64210888  610663413 7390.4
## - Accept       1 530675031 1077127556 7689.5
## 
## Step:  AIC=7331.93
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    433383  546944485 7330.4
## - S.F.Ratio    1    951440  547462542 7330.8
## - Enroll       1   1487491  547998593 7331.4
## <none>                      546511102 7331.9
## - P.Undergrad  1   2326746  548837849 7332.2
## - PhD          1   2533184  549044286 7332.4
## - Outstate     1   2853133  549364235 7332.7
## - perc.alumni  1   3150215  549661317 7333.0
## - F.Undergrad  1   3991047  550502149 7333.8
## - Grad.Rate    1   7937553  554448655 7337.5
## - PrivateYes   1   9635459  556146561 7339.1
## - Top25perc    1   9937464  556448566 7339.4
## - Room.Board   1  12825202  559336304 7342.2
## - Expend       1  23341278  569852380 7352.0
## - Top10perc    1  64582136  611093238 7388.8
## - Accept       1 530676238 1077187340 7687.5
## 
## Step:  AIC=7330.35
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - S.F.Ratio    1    982125  547926610 7329.3
## - Enroll       1   1431545  548376030 7329.7
## <none>                      546944485 7330.4
## - P.Undergrad  1   2327327  549271812 7330.6
## - Outstate     1   3172333  550116818 7331.4
## - perc.alumni  1   3416108  550360593 7331.6
## - F.Undergrad  1   3812538  550757023 7332.0
## - Grad.Rate    1   8419665  555364150 7336.4
## - PrivateYes   1   9296942  556241427 7337.2
## - PhD          1   9941681  556886166 7337.8
## - Top25perc    1  10371646  557316131 7338.3
## - Room.Board   1  12437076  559381561 7340.2
## - Expend       1  23149584  570094069 7350.2
## - Top10perc    1  65616416  612560902 7388.1
## - Accept       1 530890493 1077834979 7685.8
## 
## Step:  AIC=7329.3
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Enroll       1   1450587  549377198 7328.7
## <none>                      547926610 7329.3
## - P.Undergrad  1   2245838  550172448 7329.5
## - Outstate     1   3245116  551171726 7330.4
## - perc.alumni  1   3899740  551826350 7331.0
## - F.Undergrad  1   4097368  552023979 7331.2
## - Grad.Rate    1   8648582  556575193 7335.5
## - PhD          1   9585253  557511863 7336.4
## - Top25perc    1  10349460  558276070 7337.2
## - PrivateYes   1  10657453  558584064 7337.4
## - Room.Board   1  12081867  560008477 7338.8
## - Expend       1  22707220  570633830 7348.7
## - Top10perc    1  65163124  613089734 7386.5
## - Accept       1 530582944 1078509554 7684.2
## 
## Step:  AIC=7328.69
## .outcome ~ PrivateYes + Accept + Top10perc + Top25perc + F.Undergrad + 
##     P.Undergrad + Outstate + Room.Board + PhD + perc.alumni + 
##     Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      549377198 7328.7
## - P.Undergrad  1   2280234  551657431 7328.9
## - F.Undergrad  1   2818685  552195883 7329.4
## - Outstate     1   2981798  552358995 7329.5
## - perc.alumni  1   4621727  553998924 7331.1
## - Grad.Rate    1   8656575  558033773 7334.9
## - PhD          1   9603033  558980230 7335.8
## - Top25perc    1   9904712  559281909 7336.1
## - PrivateYes   1  10580044  559957242 7336.7
## - Room.Board   1  13180044  562557242 7339.2
## - Expend       1  22690087  572067284 7348.0
## - Top10perc    1  63896529  613273727 7384.7
## - Accept       1 744200826 1293578023 7778.0
## Start:  AIC=7315.87
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1       883  539072696 7313.9
## - Books        1    432041  539503854 7314.3
## - Terminal     1    443360  539515174 7314.3
## - P.Undergrad  1   1688001  540759814 7315.5
## <none>                      539071813 7315.9
## - PhD          1   2146981  541218794 7316.0
## - perc.alumni  1   2207920  541279733 7316.0
## - S.F.Ratio    1   4249893  543321706 7318.0
## - Enroll       1   5028133  544099946 7318.8
## - Outstate     1   7008550  546080363 7320.7
## - F.Undergrad  1   7412458  546484272 7321.1
## - Top25perc    1   8504866  547576679 7322.1
## - Grad.Rate    1   9422680  548494493 7323.0
## - Room.Board   1   9466305  548538118 7323.0
## - PrivateYes   1  10198449  549270262 7323.7
## - Expend       1  39192783  578264596 7350.8
## - Top10perc    1  51089371  590161184 7361.5
## - Accept       1 516592896 1055664709 7667.4
## 
## Step:  AIC=7313.87
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    442690  539515386 7312.3
## - Books        1    447908  539520605 7312.3
## - P.Undergrad  1   1730426  540803122 7313.6
## <none>                      539072696 7313.9
## - PhD          1   2146923  541219620 7314.0
## - perc.alumni  1   2264253  541336949 7314.1
## - S.F.Ratio    1   4281890  543354587 7316.0
## - Enroll       1   5027359  544100055 7316.8
## - Outstate     1   7033899  546106595 7318.7
## - F.Undergrad  1   7490130  546562826 7319.1
## - Top25perc    1   8504843  547577540 7320.1
## - Grad.Rate    1   9436648  548509344 7321.0
## - Room.Board   1   9506322  548579018 7321.1
## - PrivateYes   1  10221881  549294577 7321.8
## - Expend       1  39254603  578327299 7348.8
## - Top10perc    1  51090357  590163053 7359.5
## - Accept       1 521413517 1060486213 7667.8
## 
## Step:  AIC=7312.3
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    362356  539877742 7310.7
## - P.Undergrad  1   1737536  541252922 7312.0
## <none>                      539515386 7312.3
## - perc.alumni  1   2497975  542013361 7312.7
## - S.F.Ratio    1   4435913  543951299 7314.6
## - Enroll       1   4959665  544475051 7315.1
## - F.Undergrad  1   7306634  546822020 7317.4
## - Outstate     1   7420851  546936237 7317.5
## - PhD          1   8695728  548211114 7318.7
## - Top25perc    1   8997129  548512515 7319.0
## - Room.Board   1   9147941  548663327 7319.1
## - Grad.Rate    1   9725452  549240838 7319.7
## - PrivateYes   1   9889656  549405042 7319.9
## - Expend       1  39128770  578644156 7347.1
## - Top10perc    1  52413282  591928668 7359.1
## - Accept       1 521622624 1061138010 7666.1
## 
## Step:  AIC=7310.66
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - P.Undergrad  1   1800479  541678222 7310.4
## <none>                      539877742 7310.7
## - perc.alumni  1   2653139  542530881 7311.2
## - S.F.Ratio    1   4480116  544357858 7313.0
## - Enroll       1   4900049  544777792 7313.4
## - F.Undergrad  1   7427118  547304860 7315.8
## - Outstate     1   7599600  547477343 7316.0
## - PhD          1   8748295  548626037 7317.1
## - Top25perc    1   8899430  548777172 7317.3
## - Grad.Rate    1   9681210  549558953 7318.0
## - Room.Board   1   9723443  549601185 7318.0
## - PrivateYes   1   9881000  549758743 7318.2
## - Expend       1  39849477  579727219 7346.1
## - Top10perc    1  52706204  592583947 7357.7
## - Accept       1 521978711 1061856453 7664.5
## 
## Step:  AIC=7310.41
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + Outstate + Room.Board + PhD + S.F.Ratio + perc.alumni + 
##     Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      541678222 7310.4
## - perc.alumni  1   2805185  544483407 7311.1
## - S.F.Ratio    1   4331088  546009309 7312.6
## - Enroll       1   4952838  546631060 7313.2
## - Outstate     1   7637862  549316083 7315.8
## - PhD          1   8131819  549810040 7316.2
## - Grad.Rate    1   8585709  550263930 7316.7
## - Top25perc    1   8824606  550502828 7316.9
## - F.Undergrad  1   9521474  551199696 7317.6
## - PrivateYes   1  10339507  552017729 7318.4
## - Room.Board   1  10458800  552137022 7318.5
## - Expend       1  40843834  582522055 7346.6
## - Top10perc    1  51381513  593059734 7356.1
## - Accept       1 520324837 1062003059 7662.5
## Start:  AIC=7301.25
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1     54390  524348294 7299.3
## - Personal     1    127341  524421245 7299.4
## - Terminal     1    683374  524977278 7299.9
## - S.F.Ratio    1   1065360  525359264 7300.3
## - PhD          1   1344277  525638181 7300.6
## <none>                      524293904 7301.2
## - P.Undergrad  1   2600524  526894427 7301.9
## - perc.alumni  1   2761915  527055819 7302.0
## - Outstate     1   3585424  527879328 7302.8
## - Top25perc    1   5547167  529841070 7304.8
## - Enroll       1   6476010  530769913 7305.7
## - Grad.Rate    1   6778816  531072720 7306.0
## - F.Undergrad  1   7795134  532089038 7307.0
## - PrivateYes   1   9305773  533599676 7308.5
## - Room.Board   1  12675541  536969444 7311.8
## - Expend       1  19151473  543445376 7318.1
## - Top10perc    1  46041680  570335584 7343.5
## - Accept       1 550702657 1074996560 7676.9
## 
## Step:  AIC=7299.3
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Personal + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1    107078  524455372 7297.4
## - Terminal     1    657421  525005715 7298.0
## - S.F.Ratio    1   1077670  525425963 7298.4
## - PhD          1   1373268  525721562 7298.7
## <none>                      524348294 7299.3
## - P.Undergrad  1   2622253  526970546 7299.9
## - perc.alumni  1   2807516  527155810 7300.1
## - Outstate     1   3627626  527975919 7300.9
## - Top25perc    1   5532577  529880871 7302.8
## - Enroll       1   6481953  530830246 7303.8
## - Grad.Rate    1   6781524  531129818 7304.1
## - F.Undergrad  1   7818430  532166724 7305.1
## - PrivateYes   1   9256241  533604535 7306.5
## - Room.Board   1  12875190  537223483 7310.1
## - Expend       1  19243540  543591834 7316.3
## - Top10perc    1  46208354  570556648 7341.7
## - Accept       1 550650909 1074999202 7674.9
## 
## Step:  AIC=7297.41
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    667928  525123300 7296.1
## - S.F.Ratio    1   1163376  525618747 7296.6
## - PhD          1   1377287  525832659 7296.8
## <none>                      524455372 7297.4
## - P.Undergrad  1   2526618  526981990 7297.9
## - perc.alumni  1   2714642  527170014 7298.1
## - Outstate     1   3544743  528000115 7299.0
## - Top25perc    1   5539291  529994663 7300.9
## - Enroll       1   6501900  530957271 7301.9
## - Grad.Rate    1   6904565  531359937 7302.3
## - F.Undergrad  1   7714973  532170345 7303.1
## - PrivateYes   1   9244997  533700369 7304.6
## - Room.Board   1  13025658  537481030 7308.3
## - Expend       1  19161911  543617282 7314.3
## - Top10perc    1  46185635  570641007 7339.8
## - Accept       1 557484146 1081939517 7676.3
## 
## Step:  AIC=7296.08
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - S.F.Ratio    1   1297629  526420929 7295.4
## <none>                      525123300 7296.1
## - P.Undergrad  1   2544075  527667375 7296.6
## - perc.alumni  1   2991161  528114461 7297.1
## - Outstate     1   3886909  529010209 7298.0
## - Top25perc    1   5854690  530977990 7299.9
## - Enroll       1   6301935  531425235 7300.4
## - PhD          1   6699038  531822338 7300.7
## - Grad.Rate    1   7237448  532360748 7301.3
## - F.Undergrad  1   7353991  532477291 7301.4
## - PrivateYes   1   8811477  533934777 7302.8
## - Room.Board   1  12524105  537647405 7306.5
## - Expend       1  18915775  544039075 7312.7
## - Top10perc    1  47152974  572276274 7339.3
## - Accept       1 557684660 1082807960 7674.7
## 
## Step:  AIC=7295.38
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      526420929 7295.4
## - P.Undergrad  1   2454422  528875352 7295.8
## - perc.alumni  1   3465985  529886915 7296.8
## - Outstate     1   4088622  530509551 7297.4
## - Top25perc    1   5814021  532234951 7299.2
## - PhD          1   6295532  532716461 7299.6
## - Enroll       1   6304427  532725357 7299.6
## - Grad.Rate    1   7451108  533872037 7300.8
## - F.Undergrad  1   7787946  534208875 7301.1
## - PrivateYes   1  10102573  536523502 7303.4
## - Room.Board   1  12180558  538601487 7305.4
## - Expend       1  17786384  544207313 7310.9
## - Top10perc    1  46700820  573121749 7338.1
## - Accept       1 556789742 1083210671 7672.9
## Start:  AIC=7283.38
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1     55372  494694899 7281.4
## - perc.alumni  1    171618  494811144 7281.6
## - Books        1    188688  494828214 7281.6
## - Terminal     1    276338  494915864 7281.7
## - PhD          1   1642647  496282174 7283.1
## <none>                      494639526 7283.4
## - P.Undergrad  1   3282443  497921969 7284.9
## - S.F.Ratio    1   4919730  499559257 7286.6
## - Grad.Rate    1   5602446  500241972 7287.3
## - Top25perc    1   6409245  501048771 7288.2
## - Outstate     1   7118472  501757998 7288.9
## - F.Undergrad  1   9958891  504598417 7291.9
## - PrivateYes   1  10717531  505357057 7292.7
## - Room.Board   1  11838520  506478046 7293.8
## - Enroll       1  13673441  508312967 7295.7
## - Expend       1  30486964  525126490 7312.9
## - Top10perc    1  46784169  541423696 7329.0
## - Accept       1 577650487 1072290013 7689.1
## 
## Step:  AIC=7281.44
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - perc.alumni  1    151584  494846483 7279.6
## - Books        1    161954  494856852 7279.6
## - Terminal     1    276239  494971137 7279.7
## - PhD          1   1652883  496347782 7281.2
## <none>                      494694899 7281.4
## - P.Undergrad  1   3227307  497922206 7282.9
## - S.F.Ratio    1   5079375  499774273 7284.8
## - Grad.Rate    1   5710896  500405794 7285.5
## - Top25perc    1   6397444  501092342 7286.2
## - Outstate     1   7063445  501758344 7286.9
## - F.Undergrad  1   9906580  504601479 7289.9
## - PrivateYes   1  10680526  505375424 7290.7
## - Room.Board   1  11987527  506682425 7292.1
## - Enroll       1  13683062  508377961 7293.8
## - Expend       1  30438596  525133494 7310.9
## - Top10perc    1  46737941  541432839 7327.0
## - Accept       1 582534866 1077229764 7689.6
## 
## Step:  AIC=7279.6
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    181760  495028243 7277.8
## - Terminal     1    313093  495159576 7277.9
## - PhD          1   1628272  496474754 7279.3
## <none>                      494846483 7279.6
## - P.Undergrad  1   3275324  498121807 7281.1
## - S.F.Ratio    1   5270745  500117227 7283.2
## - Grad.Rate    1   5620660  500467142 7283.5
## - Top25perc    1   6566086  501412569 7284.5
## - Outstate     1   8038461  502884944 7286.1
## - F.Undergrad  1  10014969  504861451 7288.2
## - PrivateYes   1  10941956  505788438 7289.1
## - Room.Board   1  12612546  507459028 7290.9
## - Enroll       1  14537304  509383787 7292.9
## - Expend       1  30371578  525218060 7309.0
## - Top10perc    1  46721441  541567924 7325.1
## - Accept       1 625534174 1120380656 7708.2
## 
## Step:  AIC=7277.79
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Terminal + S.F.Ratio + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    287155  495315398 7276.1
## - PhD          1   1687964  496716207 7277.6
## <none>                      495028243 7277.8
## - P.Undergrad  1   3358640  498386883 7279.4
## - S.F.Ratio    1   5316457  500344700 7281.4
## - Grad.Rate    1   5597446  500625689 7281.7
## - Top25perc    1   6517428  501545670 7282.7
## - Outstate     1   8267556  503295799 7284.5
## - F.Undergrad  1  10087066  505115309 7286.4
## - PrivateYes   1  10823462  505851704 7287.2
## - Room.Board   1  12943683  507971926 7289.4
## - Enroll       1  14554696  509582939 7291.1
## - Expend       1  30650837  525679080 7307.5
## - Top10perc    1  46904219  541932461 7323.5
## - Accept       1 625627076 1120655318 7706.4
## 
## Step:  AIC=7276.1
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      495315398 7276.1
## - P.Undergrad  1   3384975  498700373 7277.7
## - S.F.Ratio    1   5464111  500779509 7279.9
## - Grad.Rate    1   5784997  501100395 7280.2
## - PhD          1   6127696  501443094 7280.6
## - Top25perc    1   6701279  502016676 7281.2
## - Outstate     1   8669665  503985063 7283.2
## - F.Undergrad  1   9914514  505229912 7284.5
## - PrivateYes   1  10581739  505897136 7285.2
## - Room.Board   1  12662458  507977856 7287.4
## - Enroll       1  14495364  509810762 7289.3
## - Expend       1  30536983  525852381 7305.6
## - Top10perc    1  47216164  542531562 7322.1
## - Accept       1 626932637 1122248035 7705.1
## Start:  AIC=7286.5
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1     13712  497589746 7284.5
## - Terminal     1    445971  498022004 7285.0
## - Books        1    954701  498530735 7285.5
## - S.F.Ratio    1   1236977  498813011 7285.8
## - perc.alumni  1   1328936  498904969 7285.9
## - PhD          1   1698584  499274617 7286.3
## <none>                      497576034 7286.5
## - Outstate     1   2830390  500406424 7287.5
## - P.Undergrad  1   3738017  501314051 7288.4
## - F.Undergrad  1   3835242  501411276 7288.5
## - Enroll       1   3933689  501509722 7288.6
## - Top25perc    1   4995663  502571697 7289.8
## - Grad.Rate    1   7879175  505455208 7292.8
## - Room.Board   1   8433287  506009320 7293.4
## - PrivateYes   1  13336241  510912275 7298.4
## - Expend       1  15595481  513171514 7300.8
## - Top10perc    1  41501551  539077585 7326.7
## - Accept       1 512714052 1010290086 7657.7
## 
## Step:  AIC=7284.51
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    450097  498039843 7283.0
## - Books        1    942547  498532293 7283.5
## - S.F.Ratio    1   1281481  498871227 7283.9
## - perc.alumni  1   1315684  498905430 7283.9
## - PhD          1   1696282  499286028 7284.3
## <none>                      497589746 7284.5
## - Outstate     1   2816683  500406428 7285.5
## - P.Undergrad  1   3744747  501334493 7286.5
## - F.Undergrad  1   3823964  501413710 7286.5
## - Enroll       1   3938556  501528302 7286.7
## - Top25perc    1   4998956  502588702 7287.8
## - Grad.Rate    1   7940586  505530332 7290.9
## - Room.Board   1   8509481  506099227 7291.4
## - PrivateYes   1  13322572  510912318 7296.4
## - Expend       1  15582569  513172315 7298.8
## - Top10perc    1  41511569  539101315 7324.7
## - Accept       1 516841630 1014431376 7657.9
## 
## Step:  AIC=7282.99
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    840757  498880600 7281.9
## - S.F.Ratio    1   1356650  499396493 7282.4
## - perc.alumni  1   1433491  499473334 7282.5
## <none>                      498039843 7283.0
## - Outstate     1   3059864  501099707 7284.2
## - F.Undergrad  1   3652530  501692373 7284.8
## - P.Undergrad  1   3772499  501812342 7285.0
## - Enroll       1   3867935  501907778 7285.1
## - Top25perc    1   5252099  503291942 7286.5
## - PhD          1   7245670  505285513 7288.6
## - Grad.Rate    1   8131821  506171664 7289.5
## - Room.Board   1   8185512  506225355 7289.6
## - PrivateYes   1  12945660  510985503 7294.5
## - Expend       1  15371411  513411254 7297.0
## - Top10perc    1  42278947  540318790 7323.9
## - Accept       1 517516575 1015556418 7656.5
## 
## Step:  AIC=7281.88
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - S.F.Ratio    1   1423225  500303825 7281.4
## - perc.alumni  1   1537669  500418269 7281.5
## <none>                      498880600 7281.9
## - Outstate     1   3285468  502166068 7283.3
## - F.Undergrad  1   3758294  502638894 7283.8
## - Enroll       1   3848230  502728830 7283.9
## - P.Undergrad  1   3933285  502813885 7284.0
## - Top25perc    1   5298408  504179008 7285.4
## - PhD          1   7225615  506106215 7287.5
## - Grad.Rate    1   8063746  506944346 7288.3
## - Room.Board   1   8784506  507665106 7289.1
## - PrivateYes   1  12777729  511658329 7293.2
## - Expend       1  15848586  514729186 7296.4
## - Top10perc    1  43197806  542078406 7323.6
## - Accept       1 516757587 1015638187 7654.5
## 
## Step:  AIC=7281.38
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - perc.alumni  1   1876181  502180006 7281.4
## <none>                      500303825 7281.4
## - Outstate     1   3536394  503840219 7283.1
## - P.Undergrad  1   3781042  504084866 7283.3
## - Enroll       1   3960879  504264704 7283.5
## - F.Undergrad  1   4060587  504364412 7283.6
## - Top25perc    1   5148936  505452761 7284.8
## - PhD          1   6719922  507023747 7286.4
## - Grad.Rate    1   8269836  508573661 7288.0
## - Room.Board   1   8539473  508843297 7288.3
## - PrivateYes   1  14263899  514567724 7294.2
## - Expend       1  14464035  514767860 7294.4
## - Top10perc    1  42480029  542783854 7322.3
## - Accept       1 518031280 1018335105 7653.9
## 
## Step:  AIC=7281.35
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      502180006 7281.4
## - P.Undergrad  1   3932180  506112186 7283.5
## - F.Undergrad  1   4239969  506419975 7283.8
## - Enroll       1   4742479  506922485 7284.3
## - Outstate     1   5690133  507870139 7285.3
## - Top25perc    1   5832731  508012737 7285.4
## - Grad.Rate    1   6978087  509158092 7286.6
## - PhD          1   7168376  509348382 7286.8
## - Room.Board   1  10315475  512495481 7290.1
## - Expend       1  14067355  516247361 7293.9
## - PrivateYes   1  15307459  517487464 7295.2
## - Top10perc    1  42642517  544822523 7322.3
## - Accept       1 557417653 1059597659 7672.9
## Start:  AIC=7310.44
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1       310  533531048 7308.4
## - Books        1    176381  533707119 7308.6
## - P.Undergrad  1    178250  533708988 7308.6
## - S.F.Ratio    1    899385  534430123 7309.3
## - perc.alumni  1   1012545  534543283 7309.4
## - PhD          1   1026824  534557562 7309.4
## - Terminal     1   1149878  534680616 7309.6
## <none>                      533530738 7310.4
## - Enroll       1   4120551  537651288 7312.5
## - Outstate     1   5142583  538673321 7313.5
## - F.Undergrad  1   5361635  538892373 7313.7
## - Grad.Rate    1   6389820  539920558 7314.7
## - Top25perc    1   9561228  543091966 7317.8
## - PrivateYes   1  11459624  544990362 7319.6
## - Room.Board   1  12745331  546276069 7320.9
## - Expend       1  23386145  556916883 7331.0
## - Top10perc    1  58345147  591875885 7363.0
## - Accept       1 506675798 1040206536 7659.6
## 
## Step:  AIC=7308.44
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    178145  533709193 7306.6
## - P.Undergrad  1    178782  533709830 7306.6
## - S.F.Ratio    1    909286  534440334 7307.3
## - perc.alumni  1   1022680  534553728 7307.4
## - PhD          1   1026712  534557760 7307.4
## - Terminal     1   1150672  534681720 7307.6
## <none>                      533531048 7308.4
## - Enroll       1   4123487  537654535 7310.5
## - Outstate     1   5174747  538705795 7311.5
## - F.Undergrad  1   5383848  538914896 7311.7
## - Grad.Rate    1   6413072  539944120 7312.7
## - Top25perc    1   9561012  543092060 7315.8
## - PrivateYes   1  11461683  544992731 7317.6
## - Room.Board   1  12799466  546330514 7318.9
## - Expend       1  23436600  556967648 7329.0
## - Top10perc    1  58351803  591882850 7361.0
## - Accept       1 509838966 1043370014 7659.2
## 
## Step:  AIC=7306.61
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - P.Undergrad  1    174165  533883358 7304.8
## - S.F.Ratio    1    931333  534640527 7305.5
## - PhD          1   1048233  534757427 7305.6
## - perc.alumni  1   1068235  534777428 7305.7
## - Terminal     1   1101025  534810218 7305.7
## <none>                      533709193 7306.6
## - Enroll       1   4111948  537821141 7308.6
## - Outstate     1   5346418  539055612 7309.9
## - F.Undergrad  1   5425005  539134198 7309.9
## - Grad.Rate    1   6376637  540085831 7310.9
## - Top25perc    1   9537158  543246351 7313.9
## - PrivateYes   1  11340319  545049512 7315.7
## - Room.Board   1  13258334  546967527 7317.5
## - Expend       1  23711262  557420456 7327.5
## - Top10perc    1  58656681  592365874 7359.5
## - Accept       1 509684952 1043394145 7657.2
## 
## Step:  AIC=7304.78
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + Outstate + Room.Board + PhD + Terminal + S.F.Ratio + 
##     perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - S.F.Ratio    1    933136  534816494 7303.7
## - PhD          1    986374  534869732 7303.8
## - Terminal     1   1103923  534987281 7303.9
## - perc.alumni  1   1174439  535057797 7303.9
## <none>                      533883358 7304.8
## - Enroll       1   4280932  538164290 7307.0
## - Outstate     1   5382185  539265542 7308.1
## - Grad.Rate    1   6203360  540086718 7308.9
## - F.Undergrad  1   6327535  540210893 7309.0
## - Top25perc    1   9555582  543438940 7312.1
## - PrivateYes   1  11459121  545342479 7314.0
## - Room.Board   1  13771609  547654966 7316.2
## - Expend       1  23858286  557741644 7325.8
## - Top10perc    1  58497858  592381216 7357.5
## - Accept       1 509694128 1043577486 7655.3
## 
## Step:  AIC=7303.7
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + Outstate + Room.Board + PhD + Terminal + perc.alumni + 
##     Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - PhD          1    846082  535662576 7302.5
## - Terminal     1   1180951  535997445 7302.9
## - perc.alumni  1   1316699  536133193 7303.0
## <none>                      534816494 7303.7
## - Enroll       1   4275780  539092274 7305.9
## - Outstate     1   5642014  540458508 7307.2
## - Grad.Rate    1   6339911  541156405 7307.9
## - F.Undergrad  1   6717786  541534280 7308.3
## - Top25perc    1   9413301  544229795 7310.9
## - PrivateYes   1  12989961  547806455 7314.3
## - Room.Board   1  13546330  548362823 7314.9
## - Expend       1  23444396  558260890 7324.3
## - Top10perc    1  57858647  592675141 7355.7
## - Accept       1 508909539 1043726033 7653.4
## 
## Step:  AIC=7302.53
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + Outstate + Room.Board + Terminal + perc.alumni + 
##     Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - perc.alumni  1   1234029  536896604 7301.7
## <none>                      535662576 7302.5
## - Enroll       1   4312826  539975402 7304.8
## - Outstate     1   5829862  541492438 7306.2
## - Grad.Rate    1   5984258  541646834 7306.4
## - Terminal     1   6661183  542323759 7307.0
## - F.Undergrad  1   6803193  542465769 7307.2
## - Top25perc    1   9645112  545307688 7309.9
## - PrivateYes   1  12293217  547955793 7312.5
## - Room.Board   1  13531017  549193593 7313.7
## - Expend       1  23582323  559244899 7323.2
## - Top10perc    1  57063698  592726274 7353.8
## - Accept       1 508612789 1044275365 7651.7
## 
## Step:  AIC=7301.74
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + Outstate + Room.Board + Terminal + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      536896604 7301.7
## - Enroll       1   4944559  541841163 7304.6
## - Grad.Rate    1   5037065  541933669 7304.7
## - F.Undergrad  1   6974817  543871421 7306.5
## - Terminal     1   7253765  544150370 7306.8
## - Outstate     1   7787229  544683833 7307.3
## - Top25perc    1  10306378  547202982 7309.7
## - PrivateYes   1  13259418  550156022 7312.6
## - Room.Board   1  15138373  552034977 7314.4
## - Expend       1  23301491  560198095 7322.1
## - Top10perc    1  56816677  593713282 7352.7
## - Accept       1 544759778 1081656382 7668.2
## Start:  AIC=8131.69
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     Personal + PhD + Terminal + S.F.Ratio + perc.alumni + Expend + 
##     Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Personal     1       154  598776566 8129.7
## - Books        1    218993  598995405 8129.9
## - Terminal     1    492872  599269283 8130.2
## - perc.alumni  1   1632931  600409343 8131.3
## <none>                      598776411 8131.7
## - PhD          1   2164686  600941097 8131.8
## - P.Undergrad  1   2264712  601041123 8131.9
## - S.F.Ratio    1   2524598  601301009 8132.2
## - Enroll       1   5371967  604148378 8134.9
## - Outstate     1   5627274  604403686 8135.2
## - F.Undergrad  1   6362526  605138937 8135.9
## - Grad.Rate    1   8753287  607529698 8138.2
## - Top25perc    1   9271176  608047587 8138.7
## - PrivateYes   1  13219866  611996277 8142.5
## - Room.Board   1  14051744  612828156 8143.3
## - Expend       1  27754954  626531365 8156.2
## - Top10perc    1  61963032  660739443 8187.3
## - Accept       1 577987055 1176763467 8524.9
## 
## Step:  AIC=8129.69
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + Books + 
##     PhD + Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Books        1    222101  598998667 8127.9
## - Terminal     1    493300  599269866 8128.2
## - perc.alumni  1   1656836  600433402 8129.3
## <none>                      598776566 8129.7
## - PhD          1   2164627  600941193 8129.8
## - P.Undergrad  1   2302472  601079037 8129.9
## - S.F.Ratio    1   2551496  601328062 8130.2
## - Enroll       1   5375390  604151956 8132.9
## - Outstate     1   5650730  604427296 8133.2
## - F.Undergrad  1   6402985  605179551 8133.9
## - Grad.Rate    1   8790601  607567167 8136.2
## - Top25perc    1   9271021  608047587 8136.7
## - PrivateYes   1  13226572  612003138 8140.5
## - Room.Board   1  14127243  612903809 8141.3
## - Expend       1  27798530  626575096 8154.2
## - Top10perc    1  61964027  660740593 8185.3
## - Accept       1 583396531 1182173097 8525.6
## 
## Step:  AIC=8127.91
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     Terminal + S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - Terminal     1    450200  599448868 8126.3
## - perc.alumni  1   1740194  600738861 8127.6
## <none>                      598998667 8127.9
## - PhD          1   2231564  601230231 8128.1
## - P.Undergrad  1   2373454  601372121 8128.2
## - S.F.Ratio    1   2573326  601571993 8128.4
## - Enroll       1   5360289  604358956 8131.1
## - Outstate     1   5829368  604828035 8131.6
## - F.Undergrad  1   6448155  605446823 8132.2
## - Grad.Rate    1   8775993  607774660 8134.4
## - Top25perc    1   9242352  608241020 8134.9
## - PrivateYes   1  13111988  612110655 8138.6
## - Room.Board   1  14542618  613541285 8139.9
## - Expend       1  28134254  627132921 8152.8
## - Top10perc    1  62399872  661398540 8183.9
## - Accept       1 583174760 1182173427 8523.6
## 
## Step:  AIC=8126.35
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + perc.alumni + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## - perc.alumni  1   1913071  601361939 8126.2
## <none>                      599448868 8126.3
## - P.Undergrad  1   2374306  601823174 8126.7
## - S.F.Ratio    1   2672426  602121294 8126.9
## - Enroll       1   5264355  604713222 8129.5
## - Outstate     1   6192567  605641435 8130.4
## - F.Undergrad  1   6241780  605690648 8130.4
## - PhD          1   8736205  608185072 8132.8
## - Grad.Rate    1   9073572  608522440 8133.1
## - Top25perc    1   9645386  609094254 8133.7
## - PrivateYes   1  12750170  612199038 8136.7
## - Room.Board   1  14135123  613583990 8138.0
## - Expend       1  27903301  627352169 8151.0
## - Top10perc    1  63493685  662942553 8183.2
## - Accept       1 583337754 1182786622 8521.9
## 
## Step:  AIC=8126.21
## .outcome ~ PrivateYes + Accept + Enroll + Top10perc + Top25perc + 
##     F.Undergrad + P.Undergrad + Outstate + Room.Board + PhD + 
##     S.F.Ratio + Expend + Grad.Rate
## 
##               Df Sum of Sq        RSS    AIC
## <none>                      601361939 8126.2
## - P.Undergrad  1   2514321  603876260 8126.7
## - S.F.Ratio    1   3150166  604512105 8127.3
## - Enroll       1   6306097  607668037 8130.3
## - F.Undergrad  1   6429257  607791196 8130.4
## - Grad.Rate    1   7599632  608961571 8131.6
## - Outstate     1   8789144  610151083 8132.7
## - PhD          1   9265075  610627014 8133.2
## - Top25perc    1  10407214  611769153 8134.2
## - PrivateYes   1  13518384  614880323 8137.2
## - Room.Board   1  16100014  617461953 8139.7
## - Expend       1  27856132  629218071 8150.7
## - Top10perc    1  63506083  664868022 8182.9
## - Accept       1 632886309 1234248248 8544.8
s <- summary(fit.lin$finalModel)
kable(s$coefficients)
Estimate Std. Error t value Pr(>|t|)
(Intercept) -884.3047105 410.6653519 -2.153346 0.0317095
PrivateYes -541.9610039 151.2709602 -3.582717 0.0003691
Accept 1.3427678 0.0547757 24.513930 0.0000000
Enroll -0.5122095 0.2093231 -2.446980 0.0147062
Top10perc 49.8041827 6.4136915 7.765291 0.0000000
Top25perc -16.1375527 5.1335801 -3.143528 0.0017559
F.Undergrad 0.0860211 0.0348156 2.470760 0.0137735
P.Undergrad 0.0513483 0.0332327 1.545114 0.1228728
Outstate -0.0597080 0.0206685 -2.888839 0.0040134
Room.Board 0.2127280 0.0544078 3.909878 0.0001034
PhD -11.0125178 3.7128899 -2.966023 0.0031429
S.F.Ratio 25.9643984 15.0127918 1.729485 0.0842628
Expend 0.0693197 0.0134786 5.142929 0.0000004
Grad.Rate 8.7354050 3.2518962 2.686250 0.0074362

All variable shows high significance. The test error is as follows.

pred.lin <- predict(fit.lin, Test, exact = T)
RMSE.lin <- mean((pred.lin - Test$Apps)^2)
RMSE.lin
## [1] 1411877
  1. Fit a ridge regression model on the training set, with λ chosen by cross-validation. Report the test error obtained.
s <- 10^seq(10,-2, length = 100)
grid <- expand.grid(lambda = s)
set.seed(13587)
fit.ridge <- train(Apps~., data = Train, trControl = ctrl, method = "ridge", tuneGrid = grid, preProcess = c("center", "scale"))
## Loading required package: elasticnet
## Loading required package: lars
## Loaded lars 1.2
par(mar = c(5.1,4.1,1,3))
plot.enet(fit.ridge$finalModel, xvar = "penalty",use.color = TRUE)

The selected lambda penalty is 0.01. the coefficient for the Test data is as follows.

pred.ridge.coef <- predict.enet(fit.ridge$finalModel, s = 0.01,Test, type = "coef",
                                mode = "penalty")
d<- data.frame(pred.ridge.coef$coefficients)
kable(d)
pred.ridge.coef.coefficients
PrivateYes -251.849767
Accept 2864.797799
Enroll -121.453033
Top10perc 795.950845
Top25perc -235.906467
F.Undergrad 376.701506
P.Undergrad 74.337610
Outstate -160.236317
Room.Board 243.270633
Books 21.363013
Personal -8.441542
PhD -118.600307
Terminal -62.879376
S.F.Ratio 86.722045
perc.alumni -107.842789
Expend 385.209199
Grad.Rate 179.466340

The RMSE for ridge is high compared to linear regression.

pred.ridge <- predict(fit.ridge, Test)
RMSE.ridge <- mean((pred.ridge - Test$Apps)^2)
RMSE.ridge
## [1] 1650614
  1. Fit a lasso model on the training set, with λ chosen by cross-validation. Report the test error obtained, along with the number of non-zero coefficient estimates.
set.seed(13587)
fit.lasso <- train(Apps ~., data = Train, trControl = ctrl, method = "lasso", tuneLength = 20, preProcess = c("center", "scale"))
plot.enet(fit.lasso$finalModel, xvar = "penalty", use.color = TRUE)

As you see in the graph, the varaible, Personal, and, Enroll goes to zero.

pred.lasso.coef <- predict.enet(fit.lasso$finalModel, s = fit.lasso$bestTune[[1]] ,data = Test,type = "coefficients", mode = "fraction")
d <- data.frame(pred.lasso.coef$coefficients)
kable(d)
pred.lasso.coef.coefficients
PrivateYes -231.15107
Accept 2938.87588
Enroll 0.00000
Top10perc 689.32594
Top25perc -137.54066
F.Undergrad 162.61747
P.Undergrad 63.33652
Outstate -130.84013
Room.Board 197.83351
Books 11.63300
Personal 0.00000
PhD -94.26298
Terminal -46.36495
S.F.Ratio 60.27958
perc.alumni -89.62794
Expend 345.34295
Grad.Rate 129.15292

RMSE for lasso is 1585615.

pred.lasso.var <- predict(fit.lasso, Test)
RMSE.lasso <- mean((pred.lasso.var - Test$Apps)^2)
RMSE.lasso
## [1] 1585615
  1. Fit a PCR model on the training set, with M chosen by cross-validation. Report the test error obtained, along with the value of M selected by cross-validation.
set.seed(13587)
pcr.fit <- train(Apps ~ ., data = Train, trControl = ctrl, preProcess = c("center", "scale"), method = "pcr")
## Loading required package: pls
## 
## Attaching package: 'pls'
## The following object is masked from 'package:caret':
## 
##     R2
## The following object is masked from 'package:stats':
## 
##     loadings
summary(pcr.fit$finalModel)
## Data:    X dimension: 585 17 
##  Y dimension: 585 1
## Fit method: svdpc
## Number of components considered: 3
## TRAINING: % variance explained
##           1 comps  2 comps  3 comps
## X           32.72    58.07    64.81
## .outcome     2.16    76.62    77.80
pred.pcr <- predict(pcr.fit, Test)
RMSE.pcr <- mean((pred.pcr - Test$Apps)^2)
RMSE.pcr
## [1] 6918780
  1. Fit a PLS model on the training set, with M chosen by cross validation. Report the test error obtained, along with the value of M selected by cross-validation.
set.seed(13587)
pls.fit <- train(Apps ~ ., data = Train, trControl = ctrl, preProcess = c("center", "scale"), thresh = 0.95, method = "pls")
summary(pls.fit$finalModel)
## Data:    X dimension: 585 17 
##  Y dimension: 585 1
## Fit method: oscorespls
## Number of components considered: 3
## TRAINING: % variance explained
##           1 comps  2 comps  3 comps
## X           25.54    43.41    63.58
## .outcome    81.19    86.72    89.28
pred.pls <- predict(pls.fit, Test)
RMSE.pls <- mean((pred.pls - Test$Apps)^2)
RMSE.pls
## [1] 3752658
c <- c(RMSE.lin, RMSE.ridge, RMSE.lasso, RMSE.pcr, RMSE.pls)
d <- data.frame(c,row.names = c("Linear","Ridge", "Lasso", "pcr", "pls")); colnames(d) <- "RMSE"
kable(d)
RMSE
Linear 1411877
Ridge 1650614
Lasso 1585615
pcr 6918780
pls 3752658

For this model, Ridge regression is better.