Chapter 9, Problem 18E

To determine

To explain how strong is the evidence that SAT score is a good predictor of GPA and what concerns you about the graph, the statistical methodology or the conclusions reached.

Explanation of Solution

A college admission officer defending the college’s use of SAT score in the admissions process produced the graph as given in the question. It shows the mean GPAs for last year’s freshmen grouped by Sat scores. So, we can say that there does appear to be moderately strong evidence of this fact due to the fairly linear appearance of the graph. However, the data should be presented as a scatterplot, not a line graph. Additionally, the admissions officer may have chosen specific scores and GPAs to illustrate his point.