Chapter 12.3, Problem 37PB

Food and drink sales The owner of Bertha’s Restaurant is interested in whether an association exists between the amount spent on food and the amount spent on drinks for the restaurant’s customers. She decides to measure each variable for every customer in the next month. Each day she also summarizes the mean amount spent on food and the mean amount spent on drinks. Which correlation between amounts spent on food and drink do you think would be higher, the one computed for the 2500 customers in the next month, or the one computed using the means for the 30 days of the month? Why? Sketch a sample scatterplot showing what you expect for each case as part of your answer.