4. Describe the potential problem of collinearity and multiple regression. How might a
researcher test for collinearity? If collinearity is a problem, what should the researcher do?
Collinearity refers to the condition when a significant correlation exists between two or more
independent variables. This condition reduces the statistical power of significance tests for the
5. A sales manager examined age data, education level, a personality measure that
indicated introvertedness / extrovertedness, and levels of sales attained by the company’s
120-person sales force. The technique used was multiple regression analysis. After
analyzing the data, the sales manager said, “It is apparent to me that the higher level of
education and the greater the degree of extrovertedness a salesperson has, the higher will
be an individual’s level of sales. In other words, a good education and being extroverted
cause a person to sell more.” Would you agree or disagree with the sales manager’s
conclusions? Why?
The manager should consider whether age and education are correlated (collinearity), as older
salespersons may have greater education and thus the “education effect” may really be an
“age/experience effect.” It is also plausible that the extroverted salespersons are also older, as
6. The factors produced and the result of the factor loadings from factor analysis are
mathematical constructs. It is the task of the researcher to make sense out of these factors.