ABSTRACT
This chapter examines a number of the statistical tools used to test for significant differences between parametric statistics for two or more groups or subgroups. With regression and correlation analyses, difference tests are probably the inferential statistical tools used most often by researchers and managers in public administration and nonprofit organizations. The Microsoft Excel analysis programs Function Wizard and Data Analysis Tools both take differences in data sets into consideration, allowing the researcher to specify which computation procedure to follow. The paired-sample Rests in Microsoft Excel can be used to compare the means for the two variables, and calculate a p-value for the t-statistic. Typically, t-tests can be used to compare the means of only two groups at a time. They are used with small sample sizes, and they should be used with groups that are equal in size. Analysis Of Variance (ANOVA) is used for samples of any size and with any number of groups or subgroups.
