An economist conducted a study of the possible association between weekly income and weekly grocery expendiure The particular interest was whether higher income would result in shoppers spending more on groceries. A random sample of shoppers at a local supermarket was obtained, and a questionnaire was administered asking about the week. income of the shopper's family and the grocery bill for that week. The gender of the shopper was also obtained. The least squares line had a slope of 0.079. The average amount by which the grocery bill increases for an increase of $100 per week is given by: $10.0. The answer cannot be determined from the information provided. $0.079. $7.9.

Given data: The least squares line had a slope of b = 0.079. An increase of x = $100 per week Let y be the dependent variable representing the grocery bill. Let x be the independent variable representing the money per week. To compute the average amount by which the grocery bill increases for an increase of $100 per week. The regression equation is given by: y=a+bx where, y = dependent variable x = independent variable a = y-intercept b = slope For the case: The average amount by which the grocery bill (y) increases for an increase of x = $100 per week is: bx=0.079×100=7.9 Therefore, the required average amount by which the grocery bill increases for an increase of $100 per week is $7.9. Hence, the last option is correct.