# R-program for Exercise 27.19 of PSLS 3e

nitro <- read.csv("r:/Chapter 27/ex27_019.csv")
summary(nitro$pctN)
stem(nitro$pctN)
# Wilcoxon signed rank test (1-sample)
wilcox.test( nitro$pctN-78.1)
wilcox.test( nitro$pctN-78.1, conf.int=T)
wilcox.test( nitro$pctN, conf.int=T)
# sign test with exact P-value
binom.test( sum(nitro$pctN>78.1), sum(nitro$pctN!=78.1), p=0.5)