The amount of time that users of a real estate website spend on the site is believed to be normally distributed. Suppose 20 randomly-selected users of the site were asked how much time they typically spend on the site during the week, and the sample mean was found to be 5.2 hours. 1. If the population standard deviation is unknown, but the sample standard deviation is = 2.89, then a. What is the point estimate for in this problem? b. Find the margin of error for a 99% confidence interval for . Round to the nearest tenth. c. Find the 99% confidence interval for (Expressed in both forms) Part 2: A second study of the amount of time that users of a real estate website spend on the site is done 5 years later and the population standard deviation is estimated to be = 2.75. Suppose 50 randomly- selected users of the site were asked how much time they typically spend on the site during the week, and the sample mean was found to be 4.8 hours. 1. With the population standard deviation equal to 2.75, and a sample size of 50: a. What is the point estimate for in this problem? b. Find the margin of error for a 99% confidence interval for . Round to the nearest tenth. c. Find the 99% confidence interval for . (Expressed in both forms)