Greenfield, Inc., a manufacturer of a popular bathing soap, tried to find the relationship between its product's price and its sales. It supplied over 2,000 retail outlets in the United States. It collected data from 25 of these stores during one week and ran a regression using these data. For each store in the sample, it observed the independent variable Price (measured in dollars), and the dependent variable Sales (measured in thousands of dollars). There results were as follows: