Two different investigators are working on a growth study. The first measures the heights of 100 children, in inches. The second prefers the metric system, and changes the results to centimeters (multiplying by the conversion factor 2.54 centimeters per inch). A scatter diagram is plotted, showing for each child its height in inches on the horizontal axis, and height in centimeters on the vertical axis.

(a) If no mistakes are made in the conversion, what is the correlation?

(b) What happens to *r* if mistakes are made in the arithmetic?

(c) What happens to *r* if the second investigator goes out and measures the same children again, using metric equipment? PL968