Say I have 2 separate predictor variables x and y. And the response variable is z. The correlation between x and z is a; the correlation between y and z is b. How to get the p-value for a = b? By using SAS or SPSS. I believe we should use t-test. Because the correlation analysis for only 1 correlation is significant or not is compared to 0 by t-test. I kind have some ideas to work this out on paper, but it is complicated to perform and consider normality, variances, and degree of freedom. I'm looking for a software package to do this simply.