How is RAT-STATS used to determine the sample size?
Once the mean and standard deviation of the overpayment amount in the Probe or Discovery Sample have been calculated, the Full Sample size can be determined. Select the “Utility File” component from the main menu. Select the “Sample Size Estimators” component. RAT-STATS will ask for the following information: • name of audit; • total sample size – when using this feature to determine the sample size, a zero should be entered in this field; • select whether the results will be saved to disk, printed or displayed; • enter the number of strata; if sample was not stratified enter “1”; • enter a name for the strata; • enter the estimated mean of the overpayments in the Probe or Discovery Sample as calculated by the Variable Appraisals function; • enter the size of the universe (i.e., the total number of sampling units from which the Probe or Discovery Sample was selected); and • enter the estimated standard deviation of overpayments in the Probe or Discovery Sample as calculated by the Vari
