Question 1
True or False.
A low value of the correlation coefficient
r implies that
x and
y are unrelated.
◦ True
◦ False
Question 2
An academic advisor wants to predict the typical starting salary of a graduate at a top business school using the GMAT score of the school as a predictor variable. A simple linear regression of SALARY versus GMAT using 25 data points is shown below.
0 = -92040
1 = 228
s = 3213
r2 = .66
r = .81 df = 23
t = 6.67
Give a practical interpretation of
r = .81.
◦ 81% of the sample variation in SALARY can be explained by using GMAT in a straight-line model.
◦ There appears to be a positive correlation between SALARY and GMAT.
◦ We estimate SALARY to increase 81% for every 1-point increase in GMAT.
◦ We can predict SALARY correctly 81% of the time using GMAT in a straight-line model.