Code of Federal Regulations Title 45. Public Welfare 45 CFR Pt. 1356, App. C—Calculating Sample Size for NYTD Follow–Up Populations

1. Using Finite Population Correction

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

2. Not Using Finite Population Correction

The FPC is not applied when the sample is drawn from a population of over 5,000 youth.