Why do smaller standard deviations sx and sy tend to increase the value of r?

(c) Make a scatter diagram for the second set of data pairs. Verify that x 5 161, x2 5 4583, y 5 255, y2 5 12,565, and xy 5 7071.

Compute r.

(d) Compare r from part

(a) with r from part (c). Do the data for averages have a higher correlation coeffi cient than the data for individual measurements?

List some reasons why you think hours lost per individual and fuel wasted per individual might vary more than the same quantities averaged over all the people in a city.