load("ritalin_data.Rdata")
ritalin_heatmap <- heatmap(Data, Rowv=NA, Colv=NA,scale="none",xlab="Students",ylab="Exams")
alpha<-0.05

#define the groups to be compared
group1 <- 1:39
group2 <- 40:78

#find p-values for each comparison
data_p <- numeric(dim(Data)[1])
for (i in 1:40) {
 data_p[i]<-t.test(Data[i,group1],Data[i,group2])$p.value
}

#check for significant comparisons
sig_tets<-which(data_p < alpha)

#number of significant tests
num_sig<-sum(data_p < alpha)