i need help solving this problem

A class survey in a large class of four-year university students asked, "About how many hours do you study during a typical week?" The mean response of the 463 students was 15.3 hours per week. Suppose that we know that the study time of all first-year students at the university follows a normal distribution with a standard deviation of 8.5 hours per week. Construct a 93% confidence interval for the mean study time per week of all first-year students at the university. A. Determine the critical value: since the confidence level is not on the provided table of eight values, make sure you sketch and label an appropriate curve and show the calculator function that you used. Write the critical value using two decimals. (3 points) B. Calculate the margin of error: show the formula that you used. Round the margin of error to the tenth. (3 points) C. Calculate the confidence interval: show the formula that you used. Write the confidence as an interval containing #. (2 points) D. Interpret the results: don't forget the units. (3 points)