In Exercise 1.61 we described an informal experiment conducted at McNair Academic High School in Jersey City, New Jersey. Two freshman algebra classes were studied, one of which used laptop computers at school and at home, while the other class did not. In each class, students were given a survey at the beginning and end of the semester, measuring his or her technological level. The scores were recorded for the end of semester survey (x) and the final examination (y) for the laptop group.5 The data and the MINITAB printout are shown here.

MINITAB output for Exercise 12.28
Regression Analysis: y versus x
The regression equation is
y = -26.8 + 1.26 x

a. Construct a scatterplot for the data. Does the assumption of linearity appear to be reasonable?
b. What is the equation of the regression line used for predicting final exam score as a function of the posttest score?
c. Do the data present sufficient evidence to indicate that final exam score is linearly related to the posttest score? Use a = .01.
d. Find a 99% confidence interval for the slope of the regression line.

a-43 41343 88889 3 68 8 8 88 2828 S-896 7878 1 2 3 4 5 6 7 8 9 0 Fra E-98 97 88 100 100 78 68 47 90 94 9980076 te 0680060826 0980098699 le 1 2 3 4 5 6 7 8 9 0 Predictor Constant Coef -26.82 1.2617 SE Coef 14.76 1.92 0.086 7.49 0.000 0.1685 S#7.61912 R-Sq 75.7% R-Sq ( adj) #74.3% Analysis of Variance Source Regression DE MS 1 3254.0 3254.0 56.05 0.000 58.1 Residual Error Total 18 1044.9 19 4299.0