* do-file for Supplementary Exercise 1.145 of IPS7e
version 17 /* works also with versions 13-16 */

import delimited "R:\Chapter 1\ex01_145.csv"

* descriptive statistics
bysort sex: summarize satm gpa, detail

* boxplots
graph box satm, over(sex)
graph box gpa, over(sex)
* note that the gpa boxplot for men has three lower suspected outliers
* in Stata, but only two in Minitab; this is due to small differences in
* formulae for the calculation of percentiles (here, the quartiles)

* quantile plots
qnorm satm if sex==1
qnorm satm if sex==2
qnorm gpa if sex==1
qnorm gpa if sex==2

* normality tests
swilk satm if sex==1
swilk satm if sex==2
swilk gpa if sex==1
swilk gpa if sex==2