if(!requireNamespace('lattice', quietly = TRUE)){
   install.packages('lattice', dependencies=TRUE, repos='http://cran.rstudio.com/')
}
library(lattice)

source('../../Data/get_reading_score_data.R')
DF = get_reading_score_data()

x=DF[DF$additional_activities=='YES', 'score']
y=DF[DF$additional_activities=='NO', 'score']
res = t.test(x, y)
print(res)

histogram(~ score | additional_activities, layout=c(1, 2), data=DF, n=10)

print(var.test(x, y))