Chapter 5.2, Problem 26E

The sales manager of a large company selected a random sample of n = 10 salespeople and determined for each one the values of x = Years of sales experience and y = Annual sales (in thousands of dollars). A scatterplot of the resulting (x, y) pairs showed a linear pattern.

1. a. Suppose that the sample correlation coefficient is r = 0.75 and that the average annual sales is $\bar{y}=100$. If a particular salesperson is 2 standard deviations above the mean in terms of experience, what would you predict for that person’s annual sales?
2. b. If a particular person whose sales experience is 1.5 standard deviations below the average experience is predicted to have an annual sales value that is 1 standard deviation below the average annual sales, what is the value of r?