18. The following data are the monthly salaries y and the grade point averages x for students who obtained a bachelor’s degree in business administration with a major in information systems. The estimated regression equation for these data is yˆ  1790.5  581.1x.

yˆ

yˆ

a. Compute SST, SSR, and SSE.

b. Compute the coefficient of determination r2

. Comment on the goodness of fit.

c. What is the value of the sample correlation coefficient?