Math 1431 – Spring 2003 – Test #1 – Practice
Question 7 Answer

The least–regression line is = –3.47 x + 145.1.

r 2 = 0.23. Thus, 23% of the observed variation in the test scores is explained by a straight–line relationship with student age.

= –3.47 (25) + 145.1 = 58. Thus, the predicted score of a 25–year–old student is 58. However, this prediction is suspect because there is a possible outlier at (23, 35) and a possible influential point at (27, 65).