The linear regression equation of best fit obtained is:
y = 0.759x + 60.214
Therefore, the predicted score for a student who has studied for 1 hour and 30 minutes (90 minutes) is:
y = 0.759(90) + 60.214
y = 68.571 + 60.214
y = 128.785
Rounded to a whole number, the predicted score is 129 points.
To score at least 90 points on the exam, a "typical" student should spend:
y = 90
90 = 0.759x + 60.214
29.786 = 0.759x
x ≈ 39.266
Rounded up to the next full minute, a "typical" student should spend 40 minutes studying.