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QUESTION 13 To analyse the waiting times at a bank, the manager selected a sample of 100 custumores. The 95% confidence interval for the population mean waiting time at the bank is found to be (5.15 minutes, 6.25 minutes). If we are to increase the sample size to 150 (other factors remain unchanged), the 95% confidence interval for u would become wider. be impossible to determine. be the same. become narrower. QUESTION 14 A researcher computed 90%, 95%, 99%, and 99.5% confidence intervals for the mean recovery time (in days) for COVID-19 cases. However, he forgot to record which interval was which, and he cannot find the sample data to allow him to recreate the intervals from scratch. He now needs only the 99.5% confidence interval. Which one is it? (30.7, 35.3) O (30.3, 35.7) O (29.1, 36.9) (29.4, 36.6) QUESTION 15 An automotive repair shop has determined that the service time on an automobile is normally distributed with a mean of 100 minutes and a standard deviation of 15 minutes. What is the probability that a random sample of 9 automotive services will have a mean service time greater than 110 minutes? O 0.2525 . 0.2208 0 0.0228 Not enough information