set.seed(4)
x = matrix(rnorm(100*5),nrow=100)
set.seed(5)
y = matrix(rnorm(100*5),nrow=100)
set.seed(6)
y[81:100,]= rnorm(100, mean=3)

p = sapply(1:100, function(i) t.test(x[i,],y[i,])$p.val)
sort.p<-sort(p)

eq<-function(){(q*(1:n))/n}

rej.pvals <- sort.p[sort.p<=eq()]     #Find all the p-values which are smaller than q*i/n

> sum(match(rej.p,p)<=80)
[1] 4