Expands the Capabilities of SPSS and Excel 

Program Dynamic

This program asks the user to input an expected percentage in a population and a sample size and then calculates the margin of error for the percentage.  The margin of error is the distance from the expected percentage to the upper or lower limit of the confidence interval.  In the example below, the margin of error for a sample size of 245 and a percentage of 20 is plus or minus 5.0087 percentage points.  

ZumaStat provides such analyses for a wide variety of tests, including mean comparisons and the analysis of correlations.  For example, you can obtain margin of errors for a main effect contrast, a simple main effect contrast or an interaction contrasts in two factor or three factor analysis of variance.  You can obtain margins of errors for a single mean or the comparison of two dependent means or two independent means.  You can obtain margin of errors for correlations, regression coefficients and the difference between regression coefficients. 

The horizontal bar beneath the sample size box can be clicked to conveniently and quickly change the sample size.  ZumaStat provides an instantaneous update to the margin of error value with each click on the horizontal bar.  It is very easy to see how precision changes with different sample sizes. 

The program is unique in that few statistical packages provide precision analysis for focused contrasts.   

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