[R] prediction R-squared

Hi, I need to compute a prediction R-squared for a linear regression. I have figured out how to compute Allen's PRESS statistic (using the PRESS function in the MPV library), but also want to compute the R-squared that goes along with this statistic. I have read that this is computed like an ad

[R] correlation coefficient from qq plot

Hi, I am trying to figure out how to get the correlation coefficient for a QQ plot (residual plot). So to be more precise, I am creating the plot like this: qq.plot(rstudent(regrname), main = rformula, col=1) But want to also access (or compute) the correlation coefficient for that plot.