Cassidy <- read.csv("Cassady.csv")
Model1.1 <- lm(GPA ~ CTA.tot + BStotal, Cassidy)
Model1.1
## 
## Call:
## lm(formula = GPA ~ CTA.tot + BStotal, data = Cassidy)
## 
## Coefficients:
## (Intercept)      CTA.tot      BStotal  
##     3.61892     -0.02007      0.01347
summary(Model1.1)
## 
## Call:
## lm(formula = GPA ~ CTA.tot + BStotal, data = Cassidy)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -2.99239 -0.29138  0.01516  0.36849  0.93941 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  3.618924   0.079305  45.633  < 2e-16 ***
## CTA.tot     -0.020068   0.003065  -6.547 1.69e-10 ***
## BStotal      0.013469   0.005077   2.653  0.00828 ** 
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.4852 on 426 degrees of freedom
##   (57 observations deleted due to missingness)
## Multiple R-squared:  0.1066, Adjusted R-squared:  0.1024 
## F-statistic: 25.43 on 2 and 426 DF,  p-value: 3.706e-11
anova(Model1.1)
## Analysis of Variance Table
## 
## Response: GPA
##            Df  Sum Sq Mean Sq F value    Pr(>F)    
## CTA.tot     1  10.316 10.3159 43.8125 1.089e-10 ***
## BStotal     1   1.657  1.6570  7.0376   0.00828 ** 
## Residuals 426 100.304  0.2355                      
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
attributes(Model1.1)
## $names
##  [1] "coefficients"  "residuals"     "effects"       "rank"         
##  [5] "fitted.values" "assign"        "qr"            "df.residual"  
##  [9] "na.action"     "xlevels"       "call"          "terms"        
## [13] "model"        
## 
## $class
## [1] "lm"
Model1.1$fitted.values
##        1        3        4        5        8        9       10       11 
## 2.964641 3.125996 3.039668 3.125454 2.852730 3.152391 3.412460 3.011917 
##       12       13       14       15       16       17       19       23 
## 2.611103 3.158448 3.298923 3.312121 2.959938 3.205183 2.945928 2.904979 
##       25       26       27       28       29       30       31       34 
## 3.226064 3.245318 2.944573 3.171646 2.917635 3.198584 3.206267 3.073204 
##       35       37       38       39       41       42       43       44 
## 3.258787 3.118584 2.972594 2.870630 3.144980 3.285454 3.386064 2.871713 
##       45       46       48       50       51       52       53       54 
## 2.911849 3.166131 3.051511 3.251917 3.080345 3.131782 3.292053 3.138923 
##       55       56       57       58       59       60       61       62 
## 3.372324 3.372324 3.065521 3.212324 3.325590 3.093543 3.172459 2.918177 
##       63       65       66       67       68       69       70       71 
## 3.104844 2.985250 3.225251 3.245318 3.151849 2.937703 2.978109 3.058651 
##       72       73       74       75       76       77       79       80 
## 2.852188 3.011375 3.225251 3.253272 3.118313 3.292053 2.664979 2.998448 
##       81       83       84       86       87       88       89       90 
## 2.878041 2.737025 3.185928 3.232121 3.225793 3.106199 2.885995 2.978380 
##       91       92       93       94       95       96       97       99 
## 3.231850 3.111443 3.292053 2.924505 3.266741 3.192256 3.012730 3.053407 
##      100      101      102      103      104      106      107      108 
## 3.119126 3.053949 3.044912 2.997906 3.327757 3.058651 3.098245 2.985792 
##      109      111      112      113      114      117      118      119 
## 3.486674 2.898109 3.211782 3.185115 3.225793 3.199939 2.891781 3.191714 
##      120      121      122      123      124      125      126      127 
## 3.298923 3.118313 2.885453 3.091375 2.898651 3.118313 2.818922 3.019058 
##      128      129      130      131      132      133      134      135 
## 3.032256 2.937703 3.246673 3.084776 2.924234 2.797499 3.078448 2.891781 
##      136      137      138      139      140      141      142      143 
## 2.784843 2.925047 3.232121 3.158448 2.697160 2.978109 2.991578 2.965995 
##      144      145      147      148      149      150      151      152 
## 2.712255 2.924505 2.985521 3.139194 3.104844 3.111443 3.011104 2.817567 
##      153      155      156      158      161      162      163      164 
## 3.286538 3.366267 3.139194 3.091375 2.783759 3.271985 3.171917 3.265657 
##      165      166      167      168      169      171      172      174 
## 2.925047 2.985250 2.965453 3.104844 3.392392 3.131511 3.078448 3.205996 
##      175      176      177      178      179      180      181      182 
## 2.851646 3.073204 2.851375 2.964641 3.231850 3.292053 3.332460 2.980277 
##      183      185      186      187      188      189      190      191 
## 3.167215 2.737838 3.185115 3.118855 2.831307 3.004776 3.225793 3.231850 
##      192      193      195      196      197      198      199      200 
## 3.266199 3.111443 3.138652 3.040210 2.897838 3.144980 3.059464 3.332189 
##      202      203      204      205      207      209      210      213 
## 3.219194 2.892865 3.231850 3.058110 3.232392 3.205725 2.777973 3.132866 
##      214      215      216      217      218      219      220      221 
## 3.178516 3.238720 2.851104 3.171646 3.004505 3.251917 3.018787 2.925318 
##      222      223      224      225      226      227      228      229 
## 3.265386 2.991307 3.098787 3.126267 2.992391 3.151849 3.031172 3.025386 
##      230      231      232      233      234      235      236      237 
## 3.252188 3.158448 2.890968 3.426470 3.165047 2.925589 3.251917 3.225251 
##      238      239      240      241      242      243      244      245 
## 3.126267 3.191714 3.118313 2.957771 2.906063 3.258787 3.051511 2.972323 
##      246      247      248      250      251      252      253      254 
## 3.225251 3.151579 3.024573 3.365725 3.132053 2.911849 2.884369 3.252188 
##      255      257      258      259      260      261      262      263 
## 3.158448 2.818651 3.005318 3.112527 3.131782 3.225251 3.151579 3.205183 
##      264      265      266      267      268      269      270      271 
## 3.144980 3.125454 3.118584 3.238720 3.360210 2.984708 3.178787 2.811239 
##      272      273      274      275      276      277      279      280 
## 3.151579 3.205183 3.118313 3.365725 3.219465 3.278855 2.930833 3.004505 
##      281      282      283      286      287      289      290      291 
## 2.972052 3.111443 3.118313 3.238720 2.924234 3.312121 3.292053 3.038042 
##      292      293      294      295      296      297      298      299 
## 3.118313 2.803827 3.265657 3.192527 3.392392 2.777973 3.145792 3.105386 
##      300      301      302      303      304      305      306      307 
## 3.158448 3.086131 3.105386 3.271985 2.958854 2.931917 3.185928 3.158719 
##      308      309      310      311      312      313      315      316 
## 3.071307 3.011375 3.238991 3.238720 3.353069 2.944302 3.085047 3.392392 
##      317      318      319      320      321      323      324      325 
## 3.245589 3.171917 2.792526 3.125725 3.278855 3.259058 2.951172 2.817296 
##      326      327      328      329      330      331      332      333 
## 3.251917 3.111443 3.091917 3.234017 3.292053 3.285454 3.119126 3.231850 
##      334      335      336      337      338      340      341      342 
## 2.811239 3.305522 3.205183 3.212324 2.892323 3.165860 2.804640 3.386064 
##      343      344      345      346      347      348      349      350 
## 3.099329 3.399533 3.252188 3.091375 3.359126 2.838990 3.399533 3.392392 
##      351      352      353      354      355      356      357      358 
## 3.285454 3.392392 3.385793 3.098245 3.279397 3.018245 3.078448 3.372324 
##      360      362      363      364      365      367      369      370 
## 3.120210 3.251917 3.285725 3.111714 3.392663 3.339058 3.078448 3.191985 
##      371      372      373      374      375      376      377      378 
## 3.104844 3.231850 3.245318 2.730426 3.205725 3.245589 3.225251 3.025115 
##      379      380      382      384      385      386      387      388 
## 3.285725 3.064979 2.978109 2.977838 3.219465 3.138381 3.059193 2.992933 
##      389      390      391      392      394      395      396      397 
## 3.078177 2.958042 3.211782 2.998448 2.830494 3.131511 3.500414 3.379194 
##      398      399      400      401      402      403      404      405 
## 3.385793 3.172188 3.138652 3.386064 3.085589 3.005589 3.259600 3.352256 
##      406      407      408      409      410      411      412      413 
## 3.118584 3.372324 3.085047 3.191985 3.285454 3.312392 3.231850 3.159803 
##      414      415      416      417      418      419      420      421 
## 3.191714 3.258787 2.944573 3.124912 3.105115 3.211782 3.278855 3.399262 
##      422      423      424      425      426      427      428      429 
## 3.051240 3.025115 2.959396 3.199668 3.258787 3.266199 3.238720 3.392392 
##      430      431      432      433      434      435      436      437 
## 3.305522 3.178516 3.312121 3.238720 3.198584 3.272256 3.292053 3.206267 
##      438      439      440      441      442      445      446      447 
## 3.179329 3.365725 3.292053 3.372324 3.345657 3.158990 3.131511 3.071307 
##      448      449      450      451      452      453      454      455 
## 3.305793 3.171646 3.312121 3.071307 3.065521 3.339058 3.113069 3.426200 
##      456      457      458      459      460      461      462      463 
## 2.925860 3.231850 3.251917 2.984437 3.312392 2.931375 3.392392 3.379194 
##      464      465      466      467      468      469      470      471 
## 3.447080 3.198855 3.392392 3.379465 3.205454 3.412460 3.225251 3.305522 
##      472      473      475      476      477      478      479      480 
## 3.091375 3.392392 3.024573 3.318991 3.392392 3.425929 3.386064 3.459736 
##      481      482      483      484      485 
## 3.199397 3.312121 3.192256 2.864031 3.245318
Model1.1$residuals
##             1             3             4             5             8 
## -0.4646405061 -0.3259956916 -0.7896675749 -0.0254537419  0.4492704297 
##             9            10            11            12            13 
## -0.0283914353 -0.1124596847 -0.5119169570  0.0888967457 -0.6584484215 
##            14            15            16            17            19 
## -0.7989228998 -0.4221207716 -0.5799383942 -0.3051829226 -0.1459275978 
##            23            25            26            27            28 
## -0.8649791080  0.0989363702 -0.2453184879 -0.4445727235  0.7783537067 
##            29            30            31            34            35 
## -0.8176350301  0.1014160133  0.3937331779 -0.1232042042  0.3412126654 
##            37            38            39            41            42 
##  0.4814161689  0.9394056837 -0.6706295541 -0.5449795748 -0.4194540531 
##            43            44            45            46            48 
## -0.4960639410 -0.0717134535 -0.4118490187  0.4338687432  0.7484894275 
##            50            51            52            53            54 
##  0.4480825762  0.1496549101 -0.3317817030 -0.0920529890  0.1910774114 
##            55            56            57            58            59 
##  0.4276758805  0.6276758805  0.5244786311  0.0156761917  0.3744103817 
##            60            61            62            63            65 
##  0.7564570383  0.2275407821  0.1818230202  0.1951559904 -0.0142502384 
##            66            67            68            69            70 
## -0.2252507053 -0.3453184879  0.0481505144 -0.1377028127 -0.7281093528 
##            71            72            73            74            75 
## -0.5586514581  0.3478123794 -0.1113750073  0.5747492947  0.1467277019 
##            76            77            79            80            81 
##  0.2116871437  0.1579470110 -0.0849786411  0.6015518897 -0.0780414146 
##            83            84            86            87            88 
##  0.2209750135 -0.8859280646  0.3778793840  0.6642073450 -0.6061988838 
##            89            90            91            92            93 
## -0.0859952248 -0.0783803277 -0.4318496412 -0.6114429455 -0.1220529890 
##            94            95            96            97            99 
## -0.9245049409  0.1932588552 -0.1922560257 -0.1127298815 -0.1534073965 
##           100           101           102           103           104 
##  0.6808742192 -0.0539493462 -0.2449116366  0.1020938394 -0.6277574172 
##           106           107           108           109           111 
##  0.3413485419  0.4017549264  0.0142078119 -0.4866738290  0.0018908028 
##           112           113           114           117           118 
## -0.5017818586  0.5148848600 -0.3257926550 -0.4999388610 -0.6417812361 
##           119           120           121           122           123 
##  0.4682859240  0.2010771002 -0.2183128563  0.1145467249  0.8086248371 
##           124           125           126           127           128 
## -0.9986511469  0.1816871437 -0.3189219661 -0.0190578426 -0.5322557144 
##           129           130           131           132           133 
## -0.7877028127  0.0533266379 -0.7507762269 -0.4742339660  0.4025006907 
##           134           135           136           137           138 
## -0.0784482659 -0.1917812361  0.0151566129  0.3749531094 -0.1321206160 
##           139           140           141           142           143 
##  0.6415515785  0.0028396038  0.2218906472  0.8304218005  0.0340046196 
##           144           145           147           148           149 
##  0.7877449080 -0.9245049409  0.5904787867 -0.2391935634 -0.5048440096 
##           150           151           152           153           155 
##  0.0885570545 -0.5111040324  0.2824329081 -0.2865379525  0.1297328667 
##           156           158           161           162           163 
##  0.2608064366 -0.2913751629  0.9212405123  0.2280147936 -0.3719172682 
##           164           165           166           167           168 
##  0.3343427547  0.2749531094 -0.3852502384 -0.5654534307  0.6951559904 
##           169           171           172           174           175 
## -0.8923919021  0.0684892719 -1.0784482659 -0.6409958472 -0.1516456709 
##           176           177           178           179           180 
##  0.4267957958  0.1486253040  0.0353594939 -0.4318496412 -0.0920529890 
##           181           182           183           185           186 
## -0.0324595291  0.6197228484 -0.1672151562 -0.0378379111 -0.1851151400 
##           187           188           189           190           191 
##  0.3811451940  0.5016930866  0.6452239287  0.5342073450 -0.0318496412 
##           192           193           195           196           197 
##  0.0338008049 -0.4114429455  0.5313483863 -1.0402095246 -0.3978382223 
##           198           199           200           202           203 
## -0.4449795748 -0.0374643827 -0.1321885543 -1.3191937190 -0.1778651355 
##           204           205           207           209           210 
## -0.5318496412 -0.0781095084 -0.9323915909  0.4942751276 -0.0779734763 
##           213           214           215           216           217 
## -0.1328656024 -0.8785162041  0.3612804480 -0.4511037212  0.4283537067 
##           218           219           220           221           222 
## -0.0045050965  0.1580825762  0.1812131323 -0.0423178654  0.3346137295 
##           223           224           225           226           227 
##  0.1086927754 -0.0987870234 -0.6262666665 -2.9923911241 -0.6168494856 
##           228           229           230           231           232 
##  0.2688281850  0.4746141963  0.3478116013  0.1415515785 -0.5909683116 
##           233           234           235           236           237 
## -0.7264704811 -0.0650473574  0.0644111597 -1.1519174238 -0.9252507053 
##           238           239           240           241           242 
## -0.9262666665 -0.1917140760 -0.0183128563  0.0422294047  0.2939369926 
##           243           244           245           246           247 
## -0.2587873346 -0.0715105725 -0.1723233414  0.0747492947 -0.2515785107 
##           248           250           251           252           253 
##  0.0754271209 -0.4657251836  0.1679473222 -0.2118490187  0.2156306244 
##           254           255           257           258           259 
##  0.2178116013  0.2415515785  0.5813490087  0.1946819790  0.3764731551 
##           260           261           262           263           264 
##  0.3682182970  0.1747492947 -0.3785785107 -0.1051829226  0.7210204252 
##           265           266           267           268           269 
## -0.6254537419 -0.9185838311 -0.0387195520 -0.1602101471  0.5152917113 
##           270           271           272           273           274 
##  0.0912128210 -0.5112391308  0.4484214893 -0.9051829226 -0.6183128563 
##           275           276           277           279           280 
## -0.9657251836 -0.6194646939  0.5211448828  0.0691670981 -0.2045050965 
##           281           282           283           286           287 
##  0.9279476334  0.3485570545 -0.0183128563  0.2112804480 -0.4242339660 
##           289           290           291           292           293 
## -0.6121207716 -1.4920529890 -0.2380417258 -0.1183128563  0.1761727297 
##           294           295           296           297           298 
## -0.7656572453 -1.1925270005  0.0486080979 -0.7779734763  0.3542075006 
##           299           300           301           302           303 
## -0.6353859593  0.5915515785  0.2438688988 -0.0053859593 -0.1719852064 
##           304           305           306           307           308 
##  0.3411455053  0.0680831986 -0.6859280646  0.2412806037 -0.5713073803 
##           309           310           311           312           313 
## -0.1493750073 -0.0389905268 -0.1387195520  0.2969307386 -0.1443017486 
##           315           316           317           318           319 
##  0.2149527982 -0.3923919021  0.0544105373  0.4980827318  0.4074737775 
##           320           321           323           324           325 
## -0.0257247167 -0.3988551172  0.0409416906  0.0358283406  0.5827038830 
##           326           327           328           329           330 
##  0.0480825762  0.7885570545  0.7080828874  0.2099825600  0.4679470110 
##           331           332           333           334           335 
## -0.2854540531  0.4608742192 -0.3418496412  0.2887608692  0.1944781643 
##           336           337           338           340           341 
## -0.4551829226 -0.2123238083  0.1076768142 -0.1858602820 -0.6366401949 
##           342           343           344           345           346 
##  0.3959360590  0.0006710269  0.3334672123  0.6478116013  0.5786248371 
##           347           348           349           350           351 
##  0.4408737523 -0.0389897488 -0.1995327877 -0.4923919021  0.2145459469 
##           352           353           354           355           356 
##  0.1076080979  0.2372070338 -0.4982450736  0.6806029331  0.4717550820 
##           357           358           360           362           363 
##  0.5275517341 -0.2723241195  0.5797903198  0.6680825762 -0.2857250280 
##           364           365           367           369           370 
## -0.1117139203 -0.1926628770  0.0809415350  0.2215517341 -0.4419850508 
##           371           372           373           374           375 
##  0.5951559904 -0.0238496412  0.2546815121  0.4095739494 -0.5057248724 
##           376           377           378           379           380 
##  0.3544105373 -0.3252507053 -0.3251148288 -1.0857250280 -0.1649794192 
##           382           384           385           386           387 
## -0.0881093528 -0.0278383779  0.2805353061  0.7716193611  0.7408065922 
##           388           389           390           391           392 
##  0.3070669262 -0.0781772910 -0.1580415702 -0.4117818586  0.5675518897 
##           394           395           396           397           398 
##  0.1695060111  0.3684892719 -0.0004136505  0.2208059697  0.2142070338 
##           399           400           401           402           403 
##  0.4078117570  0.5613483863  0.5139360590  0.0504108485  0.6944110041 
##           404           405           406           407           408 
## -0.1496002591 -0.0522563369 -0.5185838311 -0.0723241195  0.7149527982 
##           409           410           411           412           413 
## -0.1919850508  0.7145459469 -0.1123917465  0.1681503588 -0.0598032958 
##           414           415           416           417           418 
## -0.4917140760  0.0412126654  0.2554272765 -0.5249117922 -0.2051149844 
##           419           420           421           422           423 
##  0.2832181414  0.3211448828 -0.0992618129  0.5487604024  0.2748851712 
##           424           425           426           427           428 
##  0.6376035555  0.7003321139 -0.7587873346  0.1338008049  0.5612804480 
##           429           430           431           432           433 
##  0.0066080979 -0.0055218357  0.5214837959  0.1878792284  0.2612804480 
##           434           435           436           437           438 
## -0.2085839867  0.4747438187  0.4969470110 -0.9062668221  0.5206708713 
##           439           440           441           442           445 
## -0.2257251836 -0.1820529890  0.0276758805  0.5543425990  0.6310096288 
##           446           447           448           449           450 
##  0.0014892719  0.1286926197  0.4442071894 -0.1716462933 -0.5121207716 
##           451           452           453           454           455 
## -0.3713073803  0.1534786311  0.2609415350  0.6369312054  0.5338004937 
##           456           457           458           459           460 
##  0.5741401849 -0.0318496412  0.2480825762 -0.2844373139  0.4876082535 
##           461           462           463           464           465 
##  0.7686251484  0.4076080979  0.4208059697 -0.4470802135  0.8011450384 
##           466           467           468           469           470 
##  0.4076080979 -0.5484650051  0.6945461025  0.4505403153  0.7047492947 
##           471           472           473           475           476 
##  0.6804781643  0.4856248371  0.5776080979  0.8434271209 -0.0189906824 
##           477           478           479           480           481 
## -0.0923919021  0.5740714686  0.4139360590  0.5202638644 -0.2993969113 
##           482           483           484           485 
##  0.6018792284  0.8077439743  0.0359693818 -0.7453184879
Model1.2 <- lm(GPA ~ CTA.tot + BStotal + CTA.tot*BStotal, Cassidy)
Model1.2
## 
## Call:
## lm(formula = GPA ~ CTA.tot + BStotal + CTA.tot * BStotal, data = Cassidy)
## 
## Coefficients:
##     (Intercept)          CTA.tot          BStotal  CTA.tot:BStotal  
##       3.8977792       -0.0267935       -0.0057595        0.0004328
summary(Model1.2)
## 
## Call:
## lm(formula = GPA ~ CTA.tot + BStotal + CTA.tot * BStotal, data = Cassidy)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -2.98711 -0.29737  0.01801  0.36340  0.95016 
## 
## Coefficients:
##                   Estimate Std. Error t value Pr(>|t|)    
## (Intercept)      3.8977792  0.2307491  16.892  < 2e-16 ***
## CTA.tot         -0.0267935  0.0060581  -4.423 1.24e-05 ***
## BStotal         -0.0057595  0.0157812  -0.365    0.715    
## CTA.tot:BStotal  0.0004328  0.0003364   1.287    0.199    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.4849 on 425 degrees of freedom
##   (57 observations deleted due to missingness)
## Multiple R-squared:  0.1101, Adjusted R-squared:  0.1038 
## F-statistic: 17.53 on 3 and 425 DF,  p-value: 9.558e-11
Model1.3 <- lm(GPA~CTA.tot + Male, Cassidy)
summary(Model1.3)
## 
## Call:
## lm(formula = GPA ~ CTA.tot + Male, data = Cassidy)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -3.01149 -0.29005  0.03038  0.35374  0.96294 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  3.740318   0.080940  46.211  < 2e-16 ***
## CTA.tot     -0.015184   0.002117  -7.173 3.16e-12 ***
## Male        -0.222594   0.047152  -4.721 3.17e-06 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.4775 on 437 degrees of freedom
##   (46 observations deleted due to missingness)
## Multiple R-squared:  0.1364, Adjusted R-squared:  0.1324 
## F-statistic: 34.51 on 2 and 437 DF,  p-value: 1.215e-14
Model1.4 <- lm(GPA~CTA.tot + Gender, Cassidy)
summary(Model1.4)
## 
## Call:
## lm(formula = GPA ~ CTA.tot + Gender, data = Cassidy)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -3.01149 -0.29005  0.03038  0.35374  0.96294 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  3.962912   0.104741  37.835  < 2e-16 ***
## CTA.tot     -0.015184   0.002117  -7.173 3.16e-12 ***
## Gender      -0.222594   0.047152  -4.721 3.17e-06 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.4775 on 437 degrees of freedom
##   (46 observations deleted due to missingness)
## Multiple R-squared:  0.1364, Adjusted R-squared:  0.1324 
## F-statistic: 34.51 on 2 and 437 DF,  p-value: 1.215e-14
library(car)
residualPlots(Model1.1)

##            Test stat Pr(>|t|)
## CTA.tot        1.108    0.268
## BStotal        0.597    0.551
## Tukey test     0.499    0.618
library(lme4)
## Loading required package: Matrix
library(nlme)
## 
## Attaching package: 'nlme'
## The following object is masked from 'package:lme4':
## 
##     lmList
Achieve <- read.csv ("Achieve.csv")
Model3.0 <- lme( fixed = geread~1, random = ~1|school, data = Achieve)
summary(Model3.0)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##        AIC      BIC    logLik
##   46274.31 46296.03 -23134.15
## 
## Random effects:
##  Formula: ~1 | school
##         (Intercept) Residual
## StdDev:   0.6257119  2.24611
## 
## Fixed effects: geread ~ 1 
##                Value  Std.Error    DF t-value p-value
## (Intercept) 4.306753 0.05497501 10160 78.3402       0
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -2.3229469 -0.6377948 -0.2137753  0.2849664  3.8811630 
## 
## Number of Observations: 10320
## Number of Groups: 160
ICC <- 0.6257119/(0.6257119+2.24611)
ICC
## [1] 0.2178798
Model3.1 <- lme( fixed = geread~gevocab, random = ~1|school, data = Achieve)
Model3.1
## Linear mixed-effects model fit by REML
##   Data: Achieve 
##   Log-restricted-likelihood: -21568.6
##   Fixed: geread ~ gevocab 
## (Intercept)     gevocab 
##   2.0233559   0.5128977 
## 
## Random effects:
##  Formula: ~1 | school
##         (Intercept) Residual
## StdDev:   0.3158785  1.94074
## 
## Number of Observations: 10320
## Number of Groups: 160
summary(Model3.1)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##       AIC      BIC   logLik
##   43145.2 43174.17 -21568.6
## 
## Random effects:
##  Formula: ~1 | school
##         (Intercept) Residual
## StdDev:   0.3158785  1.94074
## 
## Fixed effects: geread ~ gevocab 
##                 Value  Std.Error    DF  t-value p-value
## (Intercept) 2.0233559 0.04930868 10159 41.03447       0
## gevocab     0.5128977 0.00837268 10159 61.25850       0
##  Correlation: 
##         (Intr)
## gevocab -0.758
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -3.0822506 -0.5734728 -0.2103488  0.3206692  4.4334337 
## 
## Number of Observations: 10320
## Number of Groups: 160
Model3.2 <- lme( fixed = geread~gevocab + senroll, random = ~1|school, data = Achieve)
summary(Model3.2)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##       AIC      BIC    logLik
##   43162.1 43198.31 -21576.05
## 
## Random effects:
##  Formula: ~1 | school
##         (Intercept) Residual
## StdDev:   0.3167654  1.94076
## 
## Fixed effects: geread ~ gevocab + senroll 
##                  Value  Std.Error    DF  t-value p-value
## (Intercept)  2.0748819 0.11400758 10159 18.19951  0.0000
## gevocab      0.5128708 0.00837340 10159 61.25000  0.0000
## senroll     -0.0001026 0.00020511   158 -0.50012  0.6177
##  Correlation: 
##         (Intr) gevocb
## gevocab -0.327       
## senroll -0.901 -0.002
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -3.0834462 -0.5728938 -0.2103480  0.3212091  4.4335881 
## 
## Number of Observations: 10320
## Number of Groups: 160
Model3.3 <- lme( fixed = geread~gevocab, random = ~gevocab|school, data = Achieve)
Model3.3
## Linear mixed-effects model fit by REML
##   Data: Achieve 
##   Log-restricted-likelihood: -21496.43
##   Fixed: geread ~ gevocab 
## (Intercept)     gevocab 
##   2.0057064   0.5203554 
## 
## Random effects:
##  Formula: ~gevocab | school
##  Structure: General positive-definite, Log-Cholesky parametrization
##             StdDev    Corr  
## (Intercept) 0.5316531 (Intr)
## gevocab     0.1389443 -0.859
## Residual    1.9146626       
## 
## Number of Observations: 10320
## Number of Groups: 160
summary(Model3.3)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##        AIC     BIC    logLik
##   43004.85 43048.3 -21496.43
## 
## Random effects:
##  Formula: ~gevocab | school
##  Structure: General positive-definite, Log-Cholesky parametrization
##             StdDev    Corr  
## (Intercept) 0.5316531 (Intr)
## gevocab     0.1389443 -0.859
## Residual    1.9146626       
## 
## Fixed effects: geread ~ gevocab 
##                 Value  Std.Error    DF  t-value p-value
## (Intercept) 2.0057064 0.06108786 10159 32.83314       0
## gevocab     0.5203554 0.01441548 10159 36.09699       0
##  Correlation: 
##         (Intr)
## gevocab -0.866
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -3.7102091 -0.5674433 -0.2074358  0.3176380  4.6774569 
## 
## Number of Observations: 10320
## Number of Groups: 160
Model3.4 <- lme(fixed = geread~gevocab + age, random = ~gevocab + age|school, data = Achieve)
summary(Model3.4)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##        AIC      BIC    logLik
##   43015.77 43088.18 -21497.88
## 
## Random effects:
##  Formula: ~gevocab + age | school
##  Structure: General positive-definite, Log-Cholesky parametrization
##             StdDev      Corr         
## (Intercept) 0.492487773 (Intr) gevocb
## gevocab     0.137976606 -0.073       
## age         0.006387997 -0.649 -0.601
## Residual    1.914030473              
## 
## Fixed effects: geread ~ gevocab + age 
##                  Value Std.Error    DF  t-value p-value
## (Intercept)  2.9614055 0.4151887 10158  7.13267  0.0000
## gevocab      0.5191496 0.0143563 10158 36.16175  0.0000
## age         -0.0088390 0.0038396 10158 -2.30208  0.0214
##  Correlation: 
##         (Intr) gevocb
## gevocab -0.095       
## age     -0.989 -0.032
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -3.6805531 -0.5687008 -0.2091071  0.3180583  4.6850735 
## 
## Number of Observations: 10320
## Number of Groups: 160
Model3.5 <- lme(fixed = geread~gevocab + age + gevocab*age, random = ~1|school, data = Achieve)
Model3.6 <- lme( fixed = geread~gevocab + senroll + gevocab*senroll, random = ~1|school, data = Achieve)
summary(Model3.5)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##        AIC      BIC    logLik
##   43155.49 43198.94 -21571.75
## 
## Random effects:
##  Formula: ~1 | school
##         (Intercept) Residual
## StdDev:   0.3142524 1.939708
## 
## Fixed effects: geread ~ gevocab + age + gevocab * age 
##                 Value Std.Error    DF   t-value p-value
## (Intercept)  5.187208 0.8667857 10157  5.984418  0.0000
## gevocab     -0.028078 0.1881452 10157 -0.149233  0.8814
## age         -0.029368 0.0080348 10157 -3.655077  0.0003
## gevocab:age  0.005027 0.0017496 10157  2.873204  0.0041
##  Correlation: 
##             (Intr) gevocb age   
## gevocab     -0.879              
## age         -0.998  0.879       
## gevocab:age  0.877 -0.999 -0.879
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -3.0635106 -0.5706179 -0.2108349  0.3190991  4.4467448 
## 
## Number of Observations: 10320
## Number of Groups: 160
summary(Model3.6)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##        AIC      BIC    logLik
##   43175.57 43219.02 -21581.79
## 
## Random effects:
##  Formula: ~1 | school
##         (Intercept) Residual
## StdDev:    0.316492 1.940268
## 
## Fixed effects: geread ~ gevocab + senroll + gevocab * senroll 
##                      Value  Std.Error    DF   t-value p-value
## (Intercept)      1.7477004 0.17274011 10158 10.117513  0.0000
## gevocab          0.5851202 0.02986497 10158 19.592189  0.0000
## senroll          0.0005121 0.00031863   158  1.607242  0.1100
## gevocab:senroll -0.0001356 0.00005379 10158 -2.519975  0.0118
##  Correlation: 
##                 (Intr) gevocb senrll
## gevocab         -0.782              
## senroll         -0.958  0.735       
## gevocab:senroll  0.752 -0.960 -0.766
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -3.1228018 -0.5697103 -0.2090374  0.3187827  4.4358936 
## 
## Number of Observations: 10320
## Number of Groups: 160
Cgevocab <- Achieve$gevocab - mean(Achieve$gevocab)
Cage <- Achieve$age - mean(Achieve$age)

Model3.5.C <- lme( fixed = geread~Cgevocab + Cage + Cgevocab*Cage, random = ~1|school, data = Achieve)
summary(Model3.5.C)
## Linear mixed-effects model fit by REML
##  Data: Achieve 
##        AIC      BIC    logLik
##   43155.49 43198.94 -21571.75
## 
## Random effects:
##  Formula: ~1 | school
##         (Intercept) Residual
## StdDev:   0.3142524 1.939708
## 
## Fixed effects: geread ~ Cgevocab + Cage + Cgevocab * Cage 
##                   Value  Std.Error    DF   t-value p-value
## (Intercept)    4.332326 0.03206185 10157 135.12403  0.0000
## Cgevocab       0.512480 0.00837950 10157  61.15878  0.0000
## Cage          -0.006777 0.00391727 10157  -1.72999  0.0837
## Cgevocab:Cage  0.005027 0.00174965 10157   2.87320  0.0041
##  Correlation: 
##               (Intr) Cgevcb Cage 
## Cgevocab      0.008              
## Cage          0.007  0.053       
## Cgevocab:Cage 0.043  0.021  0.205
## 
## Standardized Within-Group Residuals:
##        Min         Q1        Med         Q3        Max 
## -3.0635106 -0.5706179 -0.2108349  0.3190991  4.4467448 
## 
## Number of Observations: 10320
## Number of Groups: 160
Model3.7 <- lmer(geread~gevocab +(1|school), data = Achieve)
Model3.7
## Linear mixed model fit by REML ['lmerMod']
## Formula: geread ~ gevocab + (1 | school)
##    Data: Achieve
## REML criterion at convergence: 43137.2
## Random effects:
##  Groups   Name        Std.Dev.
##  school   (Intercept) 0.3159  
##  Residual             1.9407  
## Number of obs: 10320, groups:  school, 160
## Fixed Effects:
## (Intercept)      gevocab  
##      2.0234       0.5129
library(lmerTest)
## 
## Attaching package: 'lmerTest'
## The following object is masked from 'package:lme4':
## 
##     lmer
## The following object is masked from 'package:stats':
## 
##     step
summary(Model3.7)
## Linear mixed model fit by REML ['lmerMod']
## Formula: geread ~ gevocab + (1 | school)
##    Data: Achieve
## 
## REML criterion at convergence: 43137.2
## 
## Scaled residuals: 
##     Min      1Q  Median      3Q     Max 
## -3.0823 -0.5735 -0.2103  0.3207  4.4334 
## 
## Random effects:
##  Groups   Name        Variance Std.Dev.
##  school   (Intercept) 0.09978  0.3159  
##  Residual             3.76647  1.9407  
## Number of obs: 10320, groups:  school, 160
## 
## Fixed effects:
##             Estimate Std. Error t value
## (Intercept) 2.023356   0.049309   41.03
## gevocab     0.512898   0.008373   61.26
## 
## Correlation of Fixed Effects:
##         (Intr)
## gevocab -0.758
anova(Model3.7)
## Analysis of Variance Table
##         Df Sum Sq Mean Sq F value
## gevocab  1  14134   14134  3752.6
Model3.8 <- lmer( geread~gevocab + senroll +(1|school), data = Achieve)
Model3.8
## Linear mixed model fit by REML ['merModLmerTest']
## Formula: geread ~ gevocab + senroll + (1 | school)
##    Data: Achieve
## REML criterion at convergence: 43152.1
## Random effects:
##  Groups   Name        Std.Dev.
##  school   (Intercept) 0.3168  
##  Residual             1.9408  
## Number of obs: 10320, groups:  school, 160
## Fixed Effects:
## (Intercept)      gevocab      senroll  
##   2.0748819    0.5128708   -0.0001026
summary(Model3.8)
## Linear mixed model fit by REML t-tests use Satterthwaite approximations
##   to degrees of freedom [lmerMod]
## Formula: geread ~ gevocab + senroll + (1 | school)
##    Data: Achieve
## 
## REML criterion at convergence: 43152.1
## 
## Scaled residuals: 
##     Min      1Q  Median      3Q     Max 
## -3.0834 -0.5729 -0.2103  0.3212  4.4336 
## 
## Random effects:
##  Groups   Name        Variance Std.Dev.
##  school   (Intercept) 0.1003   0.3168  
##  Residual             3.7665   1.9408  
## Number of obs: 10320, groups:  school, 160
## 
## Fixed effects:
##               Estimate Std. Error         df t value Pr(>|t|)    
## (Intercept)  2.075e+00  1.140e-01  2.370e+02   18.20   <2e-16 ***
## gevocab      5.129e-01  8.373e-03  9.798e+03   61.25   <2e-16 ***
## senroll     -1.026e-04  2.051e-04  1.650e+02   -0.50    0.618    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Correlation of Fixed Effects:
##         (Intr) gevocb
## gevocab -0.327       
## senroll -0.901 -0.002
anova(Model3.8)
## Analysis of Variance Table of type III  with  Satterthwaite 
## approximation for degrees of freedom
##          Sum Sq Mean Sq NumDF  DenDF F.value Pr(>F)    
## gevocab 14130.4 14130.4     1 9798.1  3751.6 <2e-16 ***
## senroll     0.9     0.9     1  165.2     0.3 0.6177    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
Model3.9 <- lmer(geread~gevocab + (gevocab|school), data = Achieve)
## Warning in checkConv(attr(opt, "derivs"), opt$par, ctrl = control
## $checkConv, : unable to evaluate scaled gradient
## Warning in checkConv(attr(opt, "derivs"), opt$par, ctrl = control
## $checkConv, : Model failed to converge: degenerate Hessian with 1 negative
## eigenvalues
Model3.9
## Linear mixed model fit by REML ['merModLmerTest']
## Formula: geread ~ gevocab + (gevocab | school)
##    Data: Achieve
## REML criterion at convergence: 43051.37
## Random effects:
##  Groups   Name        Std.Dev. Corr
##  school   (Intercept) 0.00000      
##           gevocab     0.07672   NaN
##  Residual             1.92909      
## Number of obs: 10320, groups:  school, 160
## Fixed Effects:
## (Intercept)      gevocab  
##      2.0251       0.5103  
## convergence code 0; 2 optimizer warnings; 0 lme4 warnings
Model3.10 <- lmer( geread~gevocab + age+(gevocab + age|school), Achieve)
## Warning in optwrap(optimizer, devfun, getStart(start, rho$lower, rho$pp), :
## convergence code 1 from bobyqa: bobyqa -- maximum number of function
## evaluations exceeded
## Warning in checkConv(attr(opt, "derivs"), opt$par, ctrl = control
## $checkConv, : unable to evaluate scaled gradient
## Warning in checkConv(attr(opt, "derivs"), opt$par, ctrl = control
## $checkConv, : Model failed to converge: degenerate Hessian with 1 negative
## eigenvalues
Model3.10
## Linear mixed model fit by REML ['merModLmerTest']
## Formula: geread ~ gevocab + age + (gevocab + age | school)
##    Data: Achieve
## REML criterion at convergence: 42996.65
## Random effects:
##  Groups   Name        Std.Dev. Corr       
##  school   (Intercept) 0.95414             
##           gevocab     0.13759   0.11      
##           age         0.01005  -0.87 -0.51
##  Residual             1.91385             
## Number of obs: 10320, groups:  school, 160
## Fixed Effects:
## (Intercept)      gevocab          age  
##     2.96893      0.51924     -0.00891  
## convergence code 1; 2 optimizer warnings; 0 lme4 warnings
Model3.12 <- lme( fixed = geread~gevocab, random = ~1|school, data = Achieve, method = "ML")
Model3.13 <- lmer( geread~gevocab + (1|school), data = Achieve, REML = FALSE)

Model3.14 <- lme( fixed = geread~gevocab, random = ~1|school, data = Achieve, method = "ML", control = list(maxIter = 100, opt = "optim"))

Model3.1 <- lme( fixed = geread~gevocab, random = ~1|school, data = Achieve, method = "ML")
Model3.2 <- lme( fixed = geread~gevocab + senroll, random = ~1|school, data = Achieve, method = "ML")
anova(Model3.1, Model3.2)
##          Model df      AIC      BIC    logLik   Test   L.Ratio p-value
## Model3.1     1  4 43132.43 43161.40 -21562.22                         
## Model3.2     2  5 43134.18 43170.39 -21562.09 1 vs 2 0.2550617  0.6135
intervals(Model3.3)
## Approximate 95% confidence intervals
## 
##  Fixed effects:
##                 lower      est.     upper
## (Intercept) 1.8859621 2.0057064 2.1254506
## gevocab     0.4920982 0.5203554 0.5486126
## attr(,"label")
## [1] "Fixed effects:"
## 
##  Random Effects:
##   Level: school 
##                               lower       est.      upper
## sd((Intercept))           0.4250700  0.5316531  0.6649611
## sd(gevocab)               0.1153701  0.1389443  0.1673356
## cor((Intercept),gevocab) -0.9178709 -0.8585096 -0.7615768
## 
##  Within-group standard error:
##    lower     est.    upper 
## 1.888327 1.914663 1.941365