9. Two experts provided subjective lists of school districts that they think are among the best in the country. For each school district the average class size, the combined SAT score, and the percentage of students who attended a four-year college were provided.

Average Combined District Class Size SAT Score Blue Springs, MO 25 1083 % Attend Four-Year College 74 Garden City, NY 18 997 77 Indianapolis, IN 30 716 40 Newport Beach, CA 26 977 51 Novi, MI 20 980 53 Piedmont, CA 28 1042 Pittsburgh, PA 21 983 75 66 Scarsdale, NY 20 1110 87 Wayne, PA 22 1040 85 Weston, MA 1 21 1031 89 Farmingdale, NY 22 947 81 Mamaroneck, NY 20 1000 69 Mayfield, OH 24 1003 48 Morristown, NJ 22 972 New Rochelle, NY 23 1039 64 55 Newtown Square, PA 17 963 79 Omaha, NE 23 1059 81 Shaker Heights, OH 23 940 82

a. Using these data, develop an estimated regression equation relating the percentage of stu- dents who attend a four-year college to the average class size and the combined SAT score.

b. Estimate the percentage of students who attend a four-year college if the average class size is 20 and the combined SAT score is 1000.