A simple random sample of size n is drawn from a population that is normally distributed. The samplemean, x, is found to be 108, and the sample standarddeviation, s, is found to be 10.

(a) Construct a 90% confidence interval about if the samplesize, n, is 18.

(b) Construct a 90% confidence interval about if the samplesize, n, is 13.

(c) Construct an 80% confidence interval about if the samplesize, n, is 18.

(d) Could we have computed the confidence intervals in parts(a)-(c) if the population had not been normallydistributed?