Physical Sciences and Mathematics Commons^™

Sample Size Calculations And Optimal Followup Time In Health Services Research Using Utilization Rates, Paula Diehr

UW Biostatistics Working Paper Series

It is not always possible to estimate the sample sizes needed in health services research because special formulas are needed, and the necessary data may not be available to use in the formulas. We provide some useful formulas for the sample size required in comparing the means of two groups. These include the special case where the two groups are not of equal size either because one is known to have a higher variability or because one group has already been chosen and its size is thus fixed. We also explore the relationship of the mean to the standard deviation …