problem-7.18

problem-7.18  No, it does not. The mean appears to be 98.2 . (See http://hypertextbook.com/facts/LenaWong.shtml for some discussion on this.)
> t.test(normtemp$temperature,conf.level=.90)

        One Sample t-test

data:  normtemp$temperature
t = 1528, df = 129, p-value < 2.2e-16
alternative hypothesis: true mean is not equal to 0
90 percent confidence interval:
 98.14 98.36
sample estimates:
mean of x
    98.25