Eugene Gates, Marketing Director of Mansfield Motors Manufacturers, Inc.’s Electrical Division, is leading a study to assess the relative importance of product features. An item on a survey questionnaire distributed to 100 of Mansfield’s customers asked them to rate the importance of “ease of maintenance” on a scale of 1 to 10 (with 1 meaning “not important” and 10 meaning “highly important”). His staff assembled the following statistics. Ease of Maintenance Mean 7.5 Standard Deviation 1.5 If Eugene concludes that the average rate of “ease of maintenance” for all customers is 7.5, he is using .