# data from Table 2.6.2

 granite <- c(33.63, 39.86, 69.32, 42.13, 58.36, 74.11)


 basalt <- c(26.15, 18.56, 17.55, 9.84, 28.29, 34.15)


 wilcox.test(granite,basalt,conf.int=TRUE,conf.level=0.9,exact=TRUE)


 rm(granite, basalt)        # remove objects when finished