Question

Assume that the population is normal. A sample of size 100 is taken. The resultant sample data has a mean of 48 and a standard deviation of 15. Construct the 99% confidence interval for the population mean.

Answer 1

This mean .005 at each tail. Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion (.005) and its Z score.

99% = mean ± 2.575 SEm

SEm = SD/√n