Dorothy Kelly sells life insurance for the Prudence Insurance Company. She sells insurance by making visits to her clients€™ homes. Dorothy believes that the number of sales should depend, to some degree, on the number of visits made. For the past several years, she has kept careful records of the number of visits x she makes each week and the number of people y who buy insurance that week. For a random sample of 15 such weeks, the x and y values are:

Complete parts (a) through (c), given ˆ‘x = 248, ˆ‘y = 97, ˆ‘x2 = 4856, ˆ‘y2 = 731, and ˆ‘xy = 1825.
(a) Draw a scatter diagram for the data.

(c) Find the sample correlation coefficient r and the coefficient of determination r2. What percentage of variation in y is explained by the least-squares model?
(d) In a week during which Dorothy makes 18 visits, how many people do you predict will buy insurance from her?

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11 19 6 13 28 5 20 14 22 7 15 29 8 25 16 3 11 85 825 6 8 5 10 6 10 7