45 CFR Appendix C to Part 1356, Calculating Sample Size for NYTD Follow-Up Populations
The Finite Population Correction (FPC) is applied when the sample is drawn from a population of one to 5,000 youth, because the sample is more than five percent of the population.
• (Py)(Pn), an estimate of the percent of responses to a dichotomous variable, is (.50)(.50) for the most conservative estimate.
• Acceptable level of error = .05 (results are plus or minus five percentage points from the actual score)
• Z = 1.645 (90 percent confidence interval)
• N = number of youth from whom the sample is being drawn
The FPC is not applied when the sample is drawn from a population of over 5,000 youth.