Question

5, What are the economic rewards (e.g., higher salaries) to obtaining an MBA degree?
This was the question of interest in an article published in the International Economic
Review (August 2008). The researchers made inferences based on wage data collected
for a sample of 3,244 individual who sat for the Graduate Management Admissions Test
(GMAT). The following sampling scheme was employed. All those who took the GMAT
exam in any of four selected time periods ( Jan. 1990, Sep.1991,Jan. 1993,and Jan.1997)
were mailed a questionnaire. Those who responded to the questionnaire were then sent
three follow-up surveys ( one survey every 3 months) . The final sample of 3,244
represents only those individuals who responded to all four surveys. ( for example,
about 5,600 took the GMAT in Jan.1990; of these , only 800 responded to all four
surveys)
For this study, describe the population of interest.
a. What method was used to collect the ample data?
b. Do you think the final sample is representative of the population?
c. Why or why not? Comment of potential biases in the sample.

Answer 1

(i)

For this study, the population of interest is all individuals obtaining an MBA degree.

(a)

The method that was used to collect the sample data : mail survey: i.e., sending the survey questionnaire to participants by mail and recording their responses

(b)

We do not think the final sample is representative of the population

(c)

Reason:

In this mail survey, non-response bias exists. Since there is no compulsion or incentive, many participants will just ignore and will not take the trouble of responding to the survey questionnaire making the response rate very low, thus making the sample non-representative of the population.