* do-file for Supplementary Exercise 13.15 of IPS7e
version 17 /* works also with versions 13-16 */

import delimited "R:\Chapter 13\ex13_015.csv"
* first we need numerical versions of the two factors
encode gender, gen(Gender)
encode group, gen(Group)

* simple interaction plot
twoway (connected mean_score Gender if Group==1) (connected mean_score Gender if Group==2)
twoway (connected mean_score Group if Gender==1) (connected mean_score Group if Gender==2)

* alternative using the overlay add-on command (findit overlay)
overlay mean_score Gender, by(Group) c(l) xlab(1,2)
overlay mean_score Group, by(Gender) c(l) xlab(1,2)

* table with marginal means
table Gender Group, contents(mean mean_score ) row col