A random sample of 25 observations is used to estimate the population variance. The sample mean and sample standard deviation are calculated as 52.5 and 3.8, respectively. Assume that the population is normally distributed.
a. Construct the 90% interval estimate for the population variance.
b. Construct the 99% interval estimate for the population variance.
c. Use your answers to discuss the impact of the confidence level on the width of the interval.