Question

A Statistics professor assigned 10 quizzes over the course of the semester. He wanted to see if there was a relationship between the total mark of all 10 quizzes and the final exam mark. There were 213 students who completed all the quizzes and wrote the final exam. The standard deviation of the total quiz marks was 15, and that of the final exam was 17. The correlation between the total quiz mark and the final exam was 0.61. Based on the least squares regression line fitted to the data of the 213 students, if a student scored 17 points above the mean of total quiz marks, then how many points above the mean on the final would you predict her final exam grade to be?

Answer 1

Her final exam grade would be 11.7521 above the mean

Explanation:

We have:

The number of students = 213

Standard deviation of total quiz = 15

Standard deviation of final exam = 17

Correlation = 0.61

0.61x17/15

= 0.6913

If the student scored 17 points above the mean of total quiz marks

17 x 0.6913

= 11.7521

Her final exam grade would be 11.7521 above the mean