Asimple random sample of size n is drawn from a population that is normally distributed. the sample mean, x overbar, is found to be 109, and the sample standard deviation, s, is found to be 10. (a) construct a 98% confidence interval about mu if the sample size, n, is 23. (b) construct a 98% confidence interval about mu if the sample size, n, is 18. (c) construct a 70% confidence interval about mu if the sample size, n, is 23. (d) could we have computed the confidence intervals in parts () if the population had not been normally distributed?