Management professors at Columbia University examined the relationship between assertiveness and leadership (Journal of Personality and Social Psychology, Feb. 2007). The sample represented 388 people enrolled in a full-time MBA program. Based on answers to a questionnaire, the researchers measured two variables for each subject: assertiveness score (x) and leadership ability score (y). A quadratic regression model was fit to the data, with the following results:

a. Conduct a test of overall model utility. Use α = .05.
b. The researchers hypothesized that leadership ability increases at a decreasing rate with assertiveness. Set up the null and alternative hypotheses to test this theory.
c. Use the reported results to conduct the test, part b. Give your conclusion (at α = .05) in the words of the problem.

Transcribed Image Text:

Independent Variable B Estimate t-value p-value .57 2.55 088 3.97 01 01 -, Model R 12