In evaluating the usefulness and validity of a questionnaire, researchers often pretest the questionnaire on different independently selected samplcs of respondcnts.

Knowledge of the differences and similarities of the samples and their respective populations is important for interpreting the questionnaire's validity. Educational and Psychological Measurement (Feb. 1998) reported on a newly developed questionnaire for measuring the career success expectations of employees. The instru ment was tested on the two independent samples described in the table.

Managers Part-Time and Professionals MBA Students . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sample size 162 109 Gcnder (% males) 95.0 68.9 Marital status (% married) 91.2

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53.4 Source: Stephens, Gregory K., Szajna. Bernadette, and Broome, Kirk M.,

"The Career Success Expectation Scale: An exploratory and Confirmatory Factor Analysis," Erlucarional and Psychological Measurement, Vol. 58,No. 1,Feb. 1998,pp. 129-141.

a. Does the population of managers and professionals from which the sample was drawn consist of more males than the part-time MBA population does?

Conduct thc appropriate test using cw = .05.

b. Describe any assumptions you made in conducting the test of part a and why you made them.

c. Does the population of managers and professionals consist of more married individuals than the part-time MBA population does? Conduct the appropriate hypothesis test using a = .Ol.

d. What assumptions must hold for the test of part c to be valid?