library(wooldridge)
library(rmarkdown)
data("cps78_85")
paged_table( cps78_85)
require(dplyr)
## Zorunlu paket yükleniyor: dplyr
## 
## Attaching package: 'dplyr'
## The following objects are masked from 'package:stats':
## 
##     filter, lag
## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union
summary(lm(lwage ~ y85*(educ + female) + exper + I(exper^2) + union, data = cps78_85  ))
## 
## Call:
## lm(formula = lwage ~ y85 * (educ + female) + exper + I(exper^2) + 
##     union, data = cps78_85)
## 
## Residuals:
##      Min       1Q   Median       3Q      Max 
## -2.56098 -0.25828  0.00864  0.26571  2.11669 
## 
## Coefficients:
##               Estimate Std. Error t value Pr(>|t|)    
## (Intercept)  4.589e-01  9.345e-02   4.911 1.05e-06 ***
## y85          1.178e-01  1.238e-01   0.952   0.3415    
## educ         7.472e-02  6.676e-03  11.192  < 2e-16 ***
## female      -3.167e-01  3.662e-02  -8.648  < 2e-16 ***
## exper        2.958e-02  3.567e-03   8.293 3.27e-16 ***
## I(exper^2)  -3.994e-04  7.754e-05  -5.151 3.08e-07 ***
## union        2.021e-01  3.029e-02   6.672 4.03e-11 ***
## y85:educ     1.846e-02  9.354e-03   1.974   0.0487 *  
## y85:female   8.505e-02  5.131e-02   1.658   0.0977 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.4127 on 1075 degrees of freedom
## Multiple R-squared:  0.4262, Adjusted R-squared:  0.4219 
## F-statistic:  99.8 on 8 and 1075 DF,  p-value: < 2.2e-16
mydata <- cps78_85 %>%
  mutate(y78 = ifelse (year == 78, 1, 0) )