library(foreign) library(tigerstats) data<-read.dta(file="http://kanggc.iptime.org/book/data/chap11-3-2.dta") data$var1 data$var2 (d<-data$var1-data$var2) (md<-mean(d)) (n<-length(d)) (dsd<-sd(d)) tc<-md/(dsd/sqrt(n)) t5<-qt(0.05, df=5, lower.tail=T) tc;t5 t.test(d, mu=0, alternative="less", conf.level=0.95) par(mfrow=c(2,1)) ptGC(tc,region="below",df=5, graph=T) ptGC(t5,region="below",df=5, graph=T)