A marketing director is going to test whether the latest policy change has reduced product returns from 23 units per week. He believes the population is normally distributed, and the standard deviation is known. If he is using an alpha of 0.10, the z value he should look up in the normal distribution table is which of the following? Question 5 options: 1) 1.28 2) 2.33 3) -1.28 4) -2.33