Hypothesis testing Consider yourself as manager of a fast-food outlet. You have recently changed the delivery process to reduce the time between placing an order and the delivery of the order. Currently, it takes 50 minutes to deliver from the time order is placed. You are aware that the population standard deviation is 12 minutes based on past records. A sample of 72 orders yielded a sample mean of 44.8 minutes under the new delivery system.

a. State the null and alternative hypotheses. b. At the 0.05 level of significance, is there evidence that the mean delivery time has improved from the previous population's mean delivery time of 50 minutes?