help please

Listed in the accompanying data table are student evaluation ratings of courses and professors, where a rating of 5 is for "excellent." Assume that each sample is a simple random sample obtained from a population with a normal distribution. a. Use the 93 course evaluations to construct a 99% confidence interval estimate of the standard deviation of the population from which the sample was obtained b. Repeat part (a) using the 93 professor evaluations. c. Compare the results from part (a) and part (b). Click the icon to view the data table, a.