A simple random sample of size n is drawn from a population that is normally distributed. The sample mean, x*, is found to be 111, and the sample standard deviation, s, is found to be 10.
a) Construct a 98% confidence interval about u if the sample size, n, is 22.
b) Construct a 98% confidence interval about u if the sample size, n, is 17.
c) Construct a 90% confidence interval about u if the sample size, n, is 22.
d) Could we have computed the confidence intervals in parts (a)-(c) if the population had not been normally distributed?