[Chapter 9] Hypothesis Test A manager of a fast-food restaurant would like to know whether the mean waiting time to place an order has changed in the past month from its previous value of 4.5 minutes. Based on experience, the manager assumes that the waiting time is normally distributed with a population standard deviation of 1.2 minutes. A random sample of 25 orders from the past month yields a mean waiting time of 5.1 minutes. Is there evidence that the mean waiting time to place an order has changed in the past month? Conduct a hypothesis test at the 0.05 level of significance. Question 11 (1 point) The appropriate set of hypotheses is __________ . O HO: u s 4.5 Ha: u > 4.5 0 H041 = 4.5 Ha: u at 4.5 O HO: u 2 4.5 Ha: u