imputation ..........\center.m ..........\CHANGES ..........\gcvfctn.m ..........\gcvridge.m ..........\index.html ..........\iridge.m ..........\mridge.m ..........\nancov.m ..........\nanmean.m ..........\nanstd.m ..........\nansum.m ..........\peigs.m ..........\pttls.m ..........\regem.m ..........\standardize.m