Internal function to undo the Case II correction for univariate direct range restriction
.attenuate_r_uvdrr(rtpa, qxa = 1, qyi = 1, ux = 1)
A vector of attenuated correlations.
Vector of fully corrected correlations.
Vector of square-root of applicant reliability coefficients for X.
Vector square-root of incumbent reliability coefficients for Y.
Vector of observed-score u ratios for X.