OK, problem has sample n = 37, , . Estimate with 99% confidence the mean.
I get
and
For a 99% confidence rating, . Therefore, the confidence interval should be
.
The book gives answer . Not much of a difference, I know; I'm just wondering whether the difference might be due to rounding assumptions or whether I've made a more fundamental mistake.
D'oh!! I have realized the error of my ways - I forgot how to do the standard deviation (hey, that was Chapter 2, I'm in Chapter 9 now )
so if I use
then s = .416
and the answer magically becomes which is what the book says. Hoorah!
It's amazing how easy it is to become confused between the standard deviation of a population and the standard deviation of a sample... at least for me