A random sample of 60 Illinois undergraduate students are selected to answer the following question: "How many hours do you spend on studying during the weekend?" The sample average of weekend studying time is 6.8 hours. Based on historical data and prior studies, the population standard deviation is believed to be 2.3 hours, Assume the number of hours each student spends studying on the weekends is independent from others. (a) Construct a 999% (two-sided) confidence interval for the overall mean weekend studying time of U of I undergraduate students. (b) Interpret the confidence interval computed in part a within the context of the exercise. That is, make a proper statement about the meaning of the confidence interval you found. (c) What is the minimum sample size required to estimate the overall average weekend studying time of Illinois undergraduate students to within 0.5 hour of the true overall mean with 994% confidence