Q1: A random sample of high school students are asked the number of hours they spent on social media. The hours are reported below:

3 5 6 7 8 10 12 13 14 15

You can assume the times are normally distributed with a standard deviation of 8.5.

a) Estimate with 90 percent confidence the mean number of hours spent on social media by all high school students. Show working!!

b) Interpret your findings in part a).

Q2: Suppose all customers visiting the local bank have to take a random number and wait in a line. There are 200 customers in the bank in any given day, however only 85 percent of the customers are served. The length of the time customers must wait to see a Bank Teller is uniformly distributed between 50 minutes and 4 hours.

a) What is the probability that a customer would have to wait between 20 minutes and 2 hours?

b) What is the probability that a customer would have to wait between 50 minutes and 3 hours?

c) Compute the expected waiting time.

d) Compute the standard deviation of the waiting time.