Question

Because of the popularity of social media among college students, there is a great deal of interest in the relation between Facebook use and academic performance. To investigate this relation, an extensive study of over 1700 students was conducted at a public university in the northeast. For one semester the time (in minutes) spent each day on Facebook was recorded for each student. The students also agreed to allow their GPA for that semester to be used in the study. The daily mean time spent on Facebook by the students was x = 70 minutes with standard deviation sx = 22 minutes. The semester GPA of the participating students had mean y = 2.9 and standard deviation sy = 0.9. The correlation between time spent on Facebook and GPA was r = -0.35.

Question 1. Calculate the slope b1 and intercept b0 of the least squares prediction line y hat = b0 + b1x where the x-variable is time spent on Facebook and the y-variable is GPA.

________ slope (use 4 decimal places in your answer)

________intercept (use 4 decimal places in your answer)

Question 2. What is the predicted GPA of a student that spends 60 minutes a day on Facebook?

__________(use 2 decimal places in your answer)

Question 3. What is the change in GPA for each additional 10 minutes per day spent on Facebook?

A - An increase of 0.143

B - A decrease of 0.0143

C - An increase of 0.0143

D - An increase of 1.43

E - A decrease of 0.143

F - A decrease of 1.43

Answer 1