Sample Size for a CrossSectional, Cohort, or （样本量CrossSectional,队列,或）.pdfVIP

Feb 16 2007 Documentation for Sample Size for a Cross-Sectional, Cohort, or Clinical Trial Studies Kevin M. Sullivan, PhD, MPH, MHA: cdckms@sph.emory.edu Minn M. Soe, MD, MPH, MCTM: msoe@sph.emory.edu This module calculates sample size for a cross-sectional study, a cohort study, or a clinical trial. The data input screen is as follows: The four values required for a sample size calculation are:  Two-sided confidence level – most individuals would choose a 95% confidence interval, but a different confidence interval could be entered.  Power – most individuals choose a power value of 80% or 90%, however, any power level can be entered.  Ratio of Unexposed to Exposed in sample – place the desired ratio of unexposed individuals to exposed individuals. If there are to be an equal number of unexposed and exposed, then enter the value of 1.0; if there are to be twice as many unexposed as exposed, enter the value of 2.0. Any other ratio can be entered.  Percent of Unexposed with Outcome – enter an estimate of the percentage of unexposed individuals that will develop (or have) the outcome of interest. For example, in a randomized control trial, you would estimate the percentage of those in the comparison group that will develop the outcome of interest during the trial. In a cohort study, enter the percentage of unexposed