19. In Chapter 6, Problem 24 (p. 154), data were shown on the relationship between the work performance of 10 workers randomly chosen from the manufacturing section of a large corporation and two possible screening tests. The data are again shown below.

In that problem you were asked to recommend which of the two tests should be used as a screening device for prospective employees for that section of the company. On the basis of the data presented, you recommended using test 2. Now the question is: Would it be better to use both test 1 and test 2, rather than test 2 alone? Explain your answer, using R2 and r2. Use a computer and statistical software to solve this problem if you have access to them. I/O