15.10 State SAT scores. Figure 14.9 (page 329) plots the average SAT Mathematics score of each state’s high school seniors against the percentage of each state’s seniors who took the exam. In addition to two clusters, the plot shows an overall roughly straight-line pattern. The least-squares regression line for predicting average SAT Math score from percentage taking is average Math SAT score=588.4 −(1.2283percentage taking) (a) What does the slope b = −1.228 tell us about the relationship between these variables? (b) In New York State, the percentage of high school seniors who took the SAT was 76%. Predict their average score. (The actual average score in New York was 502.) (c) On page 345, we mention that using least-squares regression to do prediction outside the range of available data is risky. For what range of data is it reasonable to use the least-squares regression line for predicting average SAT Math score from percentage taking?