A car dealer who sells only late-model luxury cars recently hired a new salesperson and believes that this salesperson is selling at lower markups. He knows that the long-run average markup in his lot is $5,860. He takes a random sample of 49 of the new salesperson's sales and finds an average markup of $5,260 and a standard deviation of $790. Assume the markups are normally distributed. What is the value of an appropriate test statistic for the car dealer to use to test his claim? Multiple Choice O z=-5.32 O z=-0.75 O t48 =-0.75 O t48 --5.32