Question: A random sample of size n is drawn from a population whose population standard deviation, σ, is known to be 3.8. The sample mean, x, is determined to be 59.2.

a. Compute the 90% confidence interval about µ if the sample size, n, is 45.

b. Compute the 90% confidence interval about µ if the same size, n, is 55. How does increasing the sample size affect the margin of error, E?