The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership. The dealership has historically had 820 customers per day. The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 770. Assume that the population standard deviation is 320. The value of the test statistic is Multiple Choice O tog = 1.562 O t99 =-1.562 O z = 1.562 O Z=-1.562