402). Moreover, Daly and Ree (2006) suggest that the probability proportionate to size method is particularly useful for sampling educational institutions for ensuring that a representative sampling is achieved. Therefore, Ms. Smith would assign larger colleges with higher enrollment rates a greater chance of being selected for her visits and correspondingly lower chances to smaller colleges with lower enrollments. In order to reduce the uncertainty involved and maximize the chances of each student having an equal opportunity of being selected for interview, this step is achieved by adjusting the probability of selecting a college during the initial stages of college selection based on the proportion of all students in the general population who are enrolled at the college. As a result, a college that had 40,000 students enrolled in its computer science program would be 100 times more likely to be selected by Ms. Smith than a smaller college with just 400 students so enrolled.
Identify each outcome from the statistical analysis, providing rationale for each.
The colleges initially selected by Ms. Smith, their respective enrollment rates and sorted according to the adjusted cluster unit that was assigned to each are shown in Table 1 below.
Table 1
Breakdown of college enrollment and adjusted cluster units
Number of students
Adjusted Cluster Unit
1
40000
1
13
40000
1
20
40000
1
7
30000
1.5
6
20000
2
9
20000
2
12
20000
2
14
20000
2
The above approach appears to provide the company with the precision it needs for this purpose. For instance, according to Neuman (2003), if Ms. Smith "uses probability proportionate to size and samples correctly, then each sample element or student will have an equal probability of being selected" (p. 228).
Decision Reached
Based on the foregoing breakdown, Ms. Smith would select the first ten listed colleges for her visits where she would select ten students at random who were enrolled in the colleges' computer science programs for her face-to-face interviews. Based on the positive responses she received during her interviews with the 100 students, Computers R Us proceeded with their new product launch.
References
Becker, S. & Bryman, A. (2004). Understanding research for social policy and practice: Themes, methods and approaches. Bristol, England: Policy Press.
Daly, C.J. & Dee, J.R. (2006). Greener pastures: Faculty turnover intent in urban public universities. Journal of Higher Education, 77(5), 776-777.
Neuman, W.L. (2003). Social research methods: Qualitative and quantitative approaches, 5th ed. New York: Allyn & Bacon.
