12. Effects of Clusters Refer to the Minitab-generated scatterplot on the top of the next page. The four points in the lower left corner are measurements from women, and the four points in the upper right corner are from men.

a. Examine the pattern of the four points in the lower left corner (from women) only, and subjectively determine whether there appears to be a correlation between x and y for women.

b. Examine the pattern of the four points in the upper right corner (from men) only, and subjectively determine whether there appears to be a correlation between x and y for men.

c. Find the linear correlation coefficient using only the four points in the lower left corner (for women). Will the four points in the upper left corner (for men) have the same linear correlation coefficient?

n 5 150, 60.160

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x 1 0 5 2 3 y 3 1 15 6 8 x 0 3 3 1 4 y 1 7 2 5 5 Minitab 10-2 Correlation 535 Minitab