Assumption of Equal Intervals – Calculations on Ordinal Variables

The assumption of equal intervals says that all distances between adjacent answer categories are equal in the repondents’ perception. This assumption is an attempt to justify treating ordinal variables as if they were metric variables. Doing so enables one to compute means, standard deviations and Pearson correlations on ordinal variables. This is simpler than using more appropriate techniques. Assumption of Equal […]

SPSS Cochran Q Test

SPSS Cochran Q test is a procedure for testing if the proportions of 3 or more dichotomous variables are equal in some population. These outcome variables have been measured on the same people or other statistical units. SPSS Cochran Q Test Example The principal of some university wants to know whether three examns are equally difficult. Fifteen […]