# This file is stored as  lead.R

# The data file is posted under the name 
# lead.txt.  It does not have variable names  
# on the first line.  Enter the data 
# into a data frame.

lead <- read.table("c:/stat565/lead.txt",
      header=F, col.names=c("pair", "case", "control"))
      lead$diff<-lead$case-lead$control

# Print the data frame

lead

# Paired t-testel

t.test(lead$case, lead$control, paired=T)

# Wilcoxon signed rank test

wilcox.test(lead$case, lead$control, paired=T)


# Exact binomial p-value for the sign test

sdiff<-sign(lead$diff)
n1 <- sum(sdiff > .5)
n2 <- sum(sdiff < -.5)
binom.test(n1, n1+n2, p=.5, alternative="two.sided")