CV’S:

1,SORUNUN CEVABI

birinci veri seti 401k veri seti 401k:emekli maaşlarına ilişkin kesitsel veriler

bağımsız değişkenler:

ikinci veri seti airfare veri seti airfare:uçak biletlerine ilişkin kesitsel veriler

bağımsız değişkenler:

üçüncü veri seti athlet1 veri seti athlet1 : okulların spor programlarına ilişkin kesitsel bireysel veriler

bağımsız değişkenler:

dördüncü veri seti bwght veri seti bwght:doğum ağırlığına ilişkin kesitsel bireysel veriler

bağımsız değişkenler:

beşinci veri seti jtrain veri seti jtrain:iş eğitimine ilişkin panel bireysel veriler

bağımsız değişkenler:

2.sorunun cevabı

library(wooldridge)
data("jtrain")
summary(jtrain)
##       year          fcode            employ           sales         
##  Min.   :1987   Min.   :410032   Min.   :  4.00   Min.   :  110000  
##  1st Qu.:1987   1st Qu.:410604   1st Qu.: 15.00   1st Qu.: 1550000  
##  Median :1988   Median :418084   Median : 30.00   Median : 3000000  
##  Mean   :1988   Mean   :415709   Mean   : 59.32   Mean   : 6116037  
##  3rd Qu.:1989   3rd Qu.:419309   3rd Qu.: 72.00   3rd Qu.: 7700000  
##  Max.   :1989   Max.   :419486   Max.   :525.00   Max.   :54000000  
##                                  NA's   :31       NA's   :98        
##      avgsal          scrap             rework           tothrs     
##  Min.   : 4237   Min.   : 0.0100   Min.   : 0.000   Min.   :  0.0  
##  1st Qu.:14102   1st Qu.: 0.5925   1st Qu.: 0.350   1st Qu.:  0.0  
##  Median :17773   Median : 1.4150   Median : 1.160   Median : 12.0  
##  Mean   :18873   Mean   : 3.8436   Mean   : 3.474   Mean   : 29.2  
##  3rd Qu.:22360   3rd Qu.: 4.0000   3rd Qu.: 4.000   3rd Qu.: 40.0  
##  Max.   :42583   Max.   :30.0000   Max.   :40.000   Max.   :320.0  
##  NA's   :65      NA's   :309       NA's   :348      NA's   :56     
##      union            grant             d89              d88        
##  Min.   :0.0000   Min.   :0.0000   Min.   :0.0000   Min.   :0.0000  
##  1st Qu.:0.0000   1st Qu.:0.0000   1st Qu.:0.0000   1st Qu.:0.0000  
##  Median :0.0000   Median :0.0000   Median :0.0000   Median :0.0000  
##  Mean   :0.1975   Mean   :0.1401   Mean   :0.3333   Mean   :0.3333  
##  3rd Qu.:0.0000   3rd Qu.:0.0000   3rd Qu.:1.0000   3rd Qu.:1.0000  
##  Max.   :1.0000   Max.   :1.0000   Max.   :1.0000   Max.   :1.0000  
##                                                                     
##     totrain           hrsemp            lscrap           lemploy     
##  Min.   :  0.00   Min.   :  0.000   Min.   :-4.6052   Min.   :1.386  
##  1st Qu.:  0.00   1st Qu.:  0.000   1st Qu.:-0.5234   1st Qu.:2.708  
##  Median :  8.00   Median :  3.308   Median : 0.3471   Median :3.401  
##  Mean   : 23.09   Mean   : 14.968   Mean   : 0.3937   Mean   :3.531  
##  3rd Qu.: 25.00   3rd Qu.: 18.663   3rd Qu.: 1.3863   3rd Qu.:4.277  
##  Max.   :350.00   Max.   :163.917   Max.   : 3.4012   Max.   :6.263  
##  NA's   :6        NA's   :81        NA's   :309       NA's   :31     
##      lsales         lrework           lhrsemp         lscrap_1      
##  Min.   :11.61   Min.   :-4.6052   Min.   :0.000   Min.   :-4.6052  
##  1st Qu.:14.25   1st Qu.:-0.9163   1st Qu.:0.000   1st Qu.:-0.2675  
##  Median :14.91   Median : 0.1823   Median :1.460   Median : 0.4414  
##  Mean   :15.03   Mean   : 0.1642   Mean   :1.650   Mean   : 0.5129  
##  3rd Qu.:15.86   3rd Qu.: 1.3863   3rd Qu.:2.979   3rd Qu.: 1.6094  
##  Max.   :17.80   Max.   : 3.6889   Max.   :5.105   Max.   : 3.4012  
##  NA's   :98      NA's   :350       NA's   :81      NA's   :363      
##     grant_1           clscrap            cgrant            clemploy       
##  Min.   :0.00000   Min.   :-3.3142   Min.   :-1.00000   Min.   :-0.98083  
##  1st Qu.:0.00000   1st Qu.:-0.3975   1st Qu.: 0.00000   1st Qu.:-0.02899  
##  Median :0.00000   Median :-0.1411   Median : 0.00000   Median : 0.07066  
##  Mean   :0.07643   Mean   :-0.2211   Mean   : 0.06369   Mean   : 0.08202  
##  3rd Qu.:0.00000   3rd Qu.: 0.0093   3rd Qu.: 0.00000   3rd Qu.: 0.18232  
##  Max.   :1.00000   Max.   : 2.3979   Max.   : 1.00000   Max.   : 1.67398  
##                    NA's   :363                          NA's   :181       
##     clsales            lavgsal          clavgsal           cgrant_1     
##  Min.   :-1.98287   Min.   : 8.352   Min.   :-0.40547   Min.   :0.0000  
##  1st Qu.:-0.01101   1st Qu.: 9.554   1st Qu.: 0.02228   1st Qu.:0.0000  
##  Median : 0.10711   Median : 9.785   Median : 0.05716   Median :0.0000  
##  Mean   : 0.11587   Mean   : 9.785   Mean   : 0.06026   Mean   :0.1147  
##  3rd Qu.: 0.22314   3rd Qu.:10.015   3rd Qu.: 0.09076   3rd Qu.:0.0000  
##  Max.   : 2.89670   Max.   :10.659   Max.   : 0.56891   Max.   :1.0000  
##  NA's   :226        NA's   :65       NA's   :204        NA's   :157     
##     chrsemp             clhrsemp       
##  Min.   :-88.62255   Min.   :-4.02535  
##  1st Qu.: -0.07257   1st Qu.:-0.01493  
##  Median :  0.19860   Median : 0.03479  
##  Mean   :  5.93591   Mean   : 0.50370  
##  3rd Qu.: 11.00952   3rd Qu.: 1.36811  
##  Max.   :142.00000   Max.   : 4.39445  
##  NA's   :220         NA's   :220
jtrain_reg <- lm(sales~ union+employ+totrain+avgsal,data = jtrain)
summary(jtrain_reg)
## 
## Call:
## lm(formula = sales ~ union + employ + totrain + avgsal, data = jtrain)
## 
## Residuals:
##       Min        1Q    Median        3Q       Max 
## -21152164  -2003541   -359164    794550  33167083 
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)    
## (Intercept) -3.356e+06  8.050e+05  -4.170 3.89e-05 ***
## union        2.262e+06  6.551e+05   3.454 0.000623 ***
## employ       8.412e+04  6.024e+03  13.963  < 2e-16 ***
## totrain      2.688e+04  7.772e+03   3.458 0.000614 ***
## avgsal       1.923e+02  3.784e+01   5.082 6.21e-07 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 4800000 on 336 degrees of freedom
##   (130 observations deleted due to missingness)
## Multiple R-squared:  0.6617, Adjusted R-squared:  0.6577 
## F-statistic: 164.3 on 4 and 336 DF,  p-value: < 2.2e-16

3.sorunun cevabı

sales=b0+b1union+b2employ+b3totrain+b4avgsal+u

yıllık satış=b0+b1sendikalı ise 1+b2 çalışanlar+b3çalışanın eğitimi+b4ortalama maaş+u

part2

qt(0.95,92)
## [1] 1.661585

%95 olasılıkta:

4 değişkende anlamlıdır çünkü t değerleri 1,66dan büyüktür

4.sorunun cevabı

confint(jtrain_reg)
##                     2.5 %        97.5 %
## (Intercept) -4939942.0107 -1773033.7519
## union         973941.8965  3551014.8391
## employ         72268.3225    95968.7469
## totrain        11589.6945    42165.5620
## avgsal           117.8553      266.7059
confint(jtrain_reg, level=0.99)
##                     0.5 %        99.5 %
## (Intercept) -5.441846e+06 -1271129.9710
## union        5.655175e+05  3959439.2542
## employ       6.851219e+04    99724.8812
## totrain      6.743914e+03    47011.3429
## avgsal       9.426485e+01      290.2963
library(coefplot)
## Zorunlu paket yükleniyor: ggplot2
## Loading required package: ggplot2

coefplot(jtrain_reg)
## Warning: It is deprecated to specify `guide = FALSE` to remove a guide. Please
## use `guide = "none"` instead.

## Warning: It is deprecated to specify `guide = FALSE` to remove a guide. Please
## use `guide = "none"` instead.

## Warning: It is deprecated to specify `guide = FALSE` to remove a guide. Please
## use `guide = "none"` instead.

5.sorunun cevabı

jtrain_reg <- lm(sales~ union+employ+totrain+avgsal,data = jtrain)
summary(jtrain_reg)
## 
## Call:
## lm(formula = sales ~ union + employ + totrain + avgsal, data = jtrain)
## 
## Residuals:
##       Min        1Q    Median        3Q       Max 
## -21152164  -2003541   -359164    794550  33167083 
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)    
## (Intercept) -3.356e+06  8.050e+05  -4.170 3.89e-05 ***
## union        2.262e+06  6.551e+05   3.454 0.000623 ***
## employ       8.412e+04  6.024e+03  13.963  < 2e-16 ***
## totrain      2.688e+04  7.772e+03   3.458 0.000614 ***
## avgsal       1.923e+02  3.784e+01   5.082 6.21e-07 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 4800000 on 336 degrees of freedom
##   (130 observations deleted due to missingness)
## Multiple R-squared:  0.6617, Adjusted R-squared:  0.6577 
## F-statistic: 164.3 on 4 and 336 DF,  p-value: < 2.2e-16

t testine bakıcak olursak hepsi anlamlıdır.

kısıtlı modelimizi oluşturalım.

H0:b1=0,b2=0,b3=0

kısıtlı modelimizi oluşturalım.

sales=b0+b4avgsal+u

jtrain_kısıtlı <- lm(sales~ avgsal,data = jtrain)
summary(jtrain_kısıtlı)
## 
## Call:
## lm(formula = sales ~ avgsal, data = jtrain)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -8676510 -4328568 -3185828  1587164 48176928 
## 
## Coefficients:
##              Estimate Std. Error t value Pr(>|t|)   
## (Intercept) 2.908e+06  1.281e+06   2.271  0.02377 * 
## avgsal      1.774e+02  6.383e+01   2.779  0.00575 **
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 8102000 on 341 degrees of freedom
##   (128 observations deleted due to missingness)
## Multiple R-squared:  0.02215,    Adjusted R-squared:  0.01928 
## F-statistic: 7.723 on 1 and 341 DF,  p-value: 0.005754
r2_ur<-summary(jtrain_reg)$r.sq
r2_r<-summary(jtrain_kısıtlı)$r.sq
r2_ur
## [1] 0.6616917
r2_r
## [1] 0.02214663

üç değişken eklediğimizde (ur) modelin R2’si kısıtlı modele (r) göre çok artmıştır

n<-nobs(jtrain_reg)
n
## [1] 341

k kısıtsız modelimizde kaç tane bağımsız değişkenimiz olduğunu söyler. totrain, rework, employ, avgsal olmak üzere 4 bağımsız değişken kullandık

k<-4

Son olarak q, kaç tane kısıt kullandığımız önemlidir.toplam 3 tane kısıt kullandık.

q<-3
F_jtrain_reg<-((r2_ur-r2_r)/(1-r2_ur))*((n-k-1)/q)
F_jtrain_reg
## [1] 211.7272
qf(0.99,q,n-k-1)
## [1] 3.840401

test sonucu krtitik değerin çok üstünde hipotez reddedilecektir.

1-pf(F_jtrain_reg,q,n-k-1)
## [1] 0

H0 hipotezi reddedilir.