Question: Compute the sample correlation coefficient for the data of problem.

Problem: An article in the Journal of Monetary Economics assesses the relationship between percentage growth in wealth over a decade and a half of savings for baby boomers of age 40 to 55 with these people's income quartiles. The article presents a table showing five income quartiles, and for each quartile there is a reported percentage growth in wealth. The data are as follows.

Income quartile:               1                2                3                 4                  5

Wealth growth (%):        17.3           23.6             40.2            45.8              56.8

Run a simple linear regression of these five pairs of numbers and estimate a linear relationship between income and percentage growth in wealth.