The owner of a restaurant wants to study the characteristics of his customers. He decides to focus on two variables: the amount of money spent per diner on food and whether diners order dessert. The results from a sample of 60 diners are as follows:
Amount spent: Mean = $38.54, Standard deviation = $7.26;
18 diners purchased dessert.
(a) Do the data suggest that on average diners spend less than $40?