Fisher's z-Tests Concerning Difference of Correlations
Description
Computations of Fisher's z-tests concerning differences between correlations. diffcor.one() can be used to test whether an expected value differs from an observed value, for example, in construct validation. diffcor.two() can be used to test if the correlation between two constructs differed between two studies. diffcor.dep() can be applied to check if the correlation between two constructs (r12) is significantly different from the correlation of the first construct with a third one (r13), given the intercorrelation of the compared constructs (r23). All outputs provide the compared correlations, test statistic in z-units, and p-values. For diffcor.one() and diffcor.two(), the output further provides confidence intervals of the empirical correlations and the effect size Cohens q. According to Cohen (1988), q = |.10|, |.30| and |.50| are considered small, moderate, and large differences, respectively.