The following data represent the number of days absent, x , and the final grade, y , for a sample of college students grade in an introductory statistics class at a large state university.

No. of absences, x

0

1

2

3

4

5

6

7

8

Final grade, y

88.7

85.9

83.0

80.5

77.6

73.3

63.7

68.3

65.5

62.6

a. Find the least-squares regression line treating the number of absences as the explanatory variable and final grade as the response variable.

b. Interpret the slope and y-intercept, as appropriate.

c. Predict the final grade for a student who misses five class periods and compute the residual. Is the final grade above or below average for this number of absences?