Figure A.1 is titled "Required Effective Sample as a Function of the Proportion Estimated." It is a graph of a function within a coordinate plane; the horizontal axis represents proportion estimated and the vertical axis represents required effective sample size. The following comment is shown: 'Current Rule: NSDUH 2002'. A horizontal line through the graph indicates that an effective sample size of 68 is required for the current rule. The graph decreases from an infinitely large required effective sample size when the estimated proportion is close to zero and approaches a local minimum of 50 when the estimated proportion is 0.20. The graph increases for estimated proportions greater than 0.20 until a required effective sample size of 68 is reached for an estimated proportion of 0.50. The graph decreases for estimated proportions greater than 0.50 and approaches a local minimum of 50 for the required effective sample size when the estimated proportion is 0.80. The graph increases for estimated proportions greater than 0.80 and reaches an infinitely large required effective sample size when the estimated proportion is close to 1.

Back to Figure A.1

This page was last updated on May 16, 2008.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.