30. Consider the following three data sets, in which the variables of interest are x  commuting distance and y  commuting time. Based on a scatter plot and the values of s and r 2, in which situation would b ˆ

1 b ˆ b1* 0 b*0 x b*1 b*0 x

x x

simple linear regression be most (least) effective, and why?

626 CHAPTER 12 Regression and Correlation 1 2 3 x y x y x y 15 42 5 16 5 8 16 35 10 32 10 16 17 45 15 44 15 22 18 42 20 45 20 23 19 49 25 63 25 31 20 46 50 115 50 60 Sxx 17.50 1270.8333 1270.8333 Sxy 29.50 2722.5 1431.6667 1.685714 2.142295 1.126557 13.666672 7.868852 3.196729 SST 114.83 5897.5 1627.33 SSE 65.10 65.10 14.48