74 RateMyProfessors.com. A popular Web site among college students is RateMyProfessors.com (RMP). Established over 10 years ago, RMP allows students to post quantitative ratings of their instructors. In Practical Assessment, Research & Evaluation (May 2007), University of Maine researchers investigated whether instructor ratings posted on RMP are correlated with the formal in-class student evaluations of teaching (SET) that all universities are required to administer at the end of the semester. Data collected for n = 426 University of Maine instructors yielded a correlation between RMP and SET ratings of .68.

a. Give the equation of a linear model relating SET rating ( y ) to RMP rating ( x ).

b. Give a practical interpretation of the value r = .68 .

c. Is the estimated slope of the line, part

a, positive or negative? Explain.

d. A test of the null hypothesis H0: r = 0 yielded a p -value of .001. Interpret this result.

e. Compute the coefficient of determination, r 2 , for the regression analysis. Interpret the result.