simple random sample of size n is drawn from a population that is normally distributed. The sample mean, x, is found to be 106, and the sample standard deviation, s, is found to be 12.

(a) Construct a 95% confidence interval about if the sample size, n, is 26.

(b) Construct a 95% confidence interval about if the sample size, n, is 15. (c) Construct a 90% confidence interval about if the sample size, n, is 26.

(d) Should the confidence intervals in parts (a)-(c) have been computed if the population had not been normally distributed?