A simple random sample of size n is drawn from a population that is normally distributed. The sample mean, x overbar, is found to be 112, and the sample standard deviation, s, is found to be 10.
(a) Construct a 90% confidence interval about muμ if the sample size, n, is 28.
(b) Construct a 90% confidence interval about muμ if the sample size, n, is 19.
(c) Construct an 80% confidence interval about muμ if the sample size, n, is 28.
(d) Could we have computed the confidence intervals in parts (a)-(c) if the population had not been normally distributed?
