setwd("C:/Users/marcogeovanni/Desktop/Modern Guide To Econometrics/Chapter 3")
library("readstata13", lib.loc="~/R/win-library/3.2")
clothing <- read.dta13("clothing.dta")
summary(clothing)
## tsales sales margin nown
## Min. : 50000 Min. : 300 Min. :16.00 Min. : 1.000
## 1st Qu.: 495340 1st Qu.: 3904 1st Qu.:37.00 1st Qu.: 1.000
## Median : 694227 Median : 5279 Median :39.00 Median : 1.000
## Mean : 833584 Mean : 6335 Mean :38.77 Mean : 1.284
## 3rd Qu.: 976817 3rd Qu.: 7740 3rd Qu.:41.00 3rd Qu.: 1.295
## Max. :5000000 Max. :27000 Max. :66.00 Max. :10.000
## nfull npart naux hoursw
## Min. :1.000 Min. :1.000 Min. :1.000 Min. : 32.0
## 1st Qu.:1.923 1st Qu.:1.283 1st Qu.:1.333 1st Qu.: 80.0
## Median :1.956 Median :1.283 Median :1.367 Median :104.0
## Mean :2.069 Mean :1.566 Mean :1.390 Mean :121.1
## 3rd Qu.:2.066 3rd Qu.:2.000 3rd Qu.:1.367 3rd Qu.:145.2
## Max. :8.000 Max. :9.000 Max. :4.000 Max. :582.0
## hourspw inv1 inv2 ssize
## Min. : 5.708 Min. : 1000 Min. : 350 Min. : 16.0
## 1st Qu.:13.541 1st Qu.: 20000 1st Qu.: 10000 1st Qu.: 80.0
## Median :17.745 Median : 22207 Median : 22860 Median : 120.0
## Mean :18.955 Mean : 58257 Mean : 27829 Mean : 151.1
## 3rd Qu.:24.303 3rd Qu.: 62269 3rd Qu.: 22860 3rd Qu.: 190.0
## Max. :43.326 Max. :1500000 Max. :400000 Max. :1214.0
## start
## Min. :16.00
## 1st Qu.:37.00
## Median :40.00
## Mean :42.81
## 3rd Qu.:42.00
## Max. :90.00
attach(clothing)
hist(sales, col="red")
hist(hoursw, col="green")
hist(ssize, col="purple")
reg1<- lm(sales~hoursw + ssize)
summary(reg1)
##
## Call:
## lm(formula = sales ~ hoursw + ssize)
##
## Residuals:
## Min 1Q Median 3Q Max
## -5658.5 -1874.1 -466.8 937.6 18076.3
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) 5133.590 321.693 15.96 <2e-16 ***
## hoursw 37.528 2.837 13.23 <2e-16 ***
## ssize -22.145 1.625 -13.63 <2e-16 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 2985 on 397 degrees of freedom
## Multiple R-squared: 0.3658, Adjusted R-squared: 0.3626
## F-statistic: 114.5 on 2 and 397 DF, p-value: < 2.2e-16
reg3 <-lm(sales~hoursw + ssize + nown + npart)
summary(reg3)
##
## Call:
## lm(formula = sales ~ hoursw + ssize + nown + npart)
##
## Residuals:
## Min 1Q Median 3Q Max
## -6424.2 -1869.8 -492.7 1079.3 18028.7
##
## Coefficients:
## Estimate Std. Error t value Pr(>|t|)
## (Intercept) 4494.511 462.795 9.712 < 2e-16 ***
## hoursw 39.024 3.094 12.611 < 2e-16 ***
## ssize -24.324 1.694 -14.356 < 2e-16 ***
## nown -385.007 255.583 -1.506 0.132768
## npart 818.432 224.016 3.653 0.000294 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
##
## Residual standard error: 2936 on 395 degrees of freedom
## Multiple R-squared: 0.3898, Adjusted R-squared: 0.3837
## F-statistic: 63.09 on 4 and 395 DF, p-value: < 2.2e-16