Anna, a business major, took final exams in both Microeconomics and Macroeconomics and scored 83 on both. Her roommate Megan, also taking both courses, scored 77 on the micro exam and 95 on the macro exam. Overall, student scores on the Micro exam had a mean of 81 and a standard deviation of 5, and the Macro scores had a mean of 74 and a standard deviation of 15. Which students’ overall performance was better? Explain.

Grocery store receipts show that customer purchases have a skewed distribution with a mean of $32 and a standard deviation of $20. a) Explain why you cannot determine the probability that the next customer will spend at least $40 b) Can you estimate the probability that the next 10 customers will spend an average of at least $40? Explain c) Is it likely that the next 50 customers will spend an average of at least $40? Explain.