Show APPENDIXStatistical Calculations The statistical methods are presented for the calculations of the 95 percent confidence interval the statistical power and the expected number of cases Calculation of the 95 confidence interval for the standardized incidence ratio 196x0 05 Where x is the Number of Observed is the Number of Expected For further definition see Frumkin and Kantrowitz 1984 Calculation of the power to detectdifference between the observed versus the expected number of cases atSpecified SIR whentue difference really exists Power 1-p VSTR Where Z E SIR VE the Probabilty ofType Il Error or AcceptingFalse Nul Hypothesis This value is determined by usingZ table was setat1 96 for atwo-tailed test is the area beyondonNormal Distribution Curve the Expected number of Cases in county under evaluation Standardized Incidence Ratio See Beaumont and Breslow 1981 Calculation for determining the expected number of cases Utah in Expected Population in State of Utah nin Where Observed Number of Cases in State of Utah is the observed number of cases in the state of Utah for the specifc time period under evaluation Population in Specific County is the estimated population of the county under evaluation during the specific ime period Population in State of Utah is the estimated population of the state of Utah during the specific time period under evaluation 36 Digital image 2005 Marriott Library University of Utah Al rights reserved |