> n <- length(Y) > > Y_corr <- (1/sqrt(n-1))*(Y-mean(Y))/sd(Y) # Correlation transformation for Y > X1_corr <- (1/sqrt(n-1))*(X1-mean(X1))/sd(X1) # Correlation transformation for X1 > X2_corr <- (1/sqrt(n-1))*(X2-mean(X2))/sd(X2) # Correlation transformation for X2 > > print(cbind(Y_corr,X1_corr,X2_corr)) Y_corr X1_corr X2_corr [1,] -0.046367928 0.07782811 -0.102052117 [2,] -0.108152604 -0.20197568 -0.079008091 [3,] 0.384889109 0.35162753 0.243608280 [4,] -0.168701586 -0.17075294 -0.194228224 [5,] -0.001882962 -0.18156081 0.036212042 [6,] 0.158139349 0.04900712 0.243608280 [7,] -0.179822828 -0.15033807 -0.286404330 [8,] -0.115566765 -0.12031620 0.013168015 [9,] -0.225543488 -0.15754332 -0.125096144 [10,] -0.276206922 -0.28363515 -0.263360303 [11,] 0.370678634 0.31079779 0.266652307 [12,] 0.056812480 0.12946572 -0.009876011 [13,] 0.309511805 0.31680217 0.059256068 [14,] -0.226161335 -0.22959579 -0.309448356 [15,] -0.128541547 -0.11431183 0.151432174 [16,] 0.171731978 0.28437855 0.289696333 [17,] -0.219365020 -0.24880979 -0.148140170 [18,] -0.234193343 -0.12391883 -0.194228224 [19,] 0.313218885 0.33121266 0.220564254 [20,] 0.260701911 0.24835231 0.451004519 [21,] -0.095177822 -0.11671358 -0.263360303 > > dwaine.stdreg <- lm(Y_corr ~ X1_corr + X2_corr -1) # Regression of Y* on X1*,X2*, no intercept > summary(dwaine.stdreg) Call: lm(formula = Y_corr ~ X1_corr + X2_corr - 1) Residuals: Min 1Q Median 3Q Max -0.113831 -0.038406 0.004602 0.058298 0.124898 Coefficients: Estimate Std. Error t value Pr(>|t|) X1_corr 0.7484 0.1061 7.056 1.03e-06 *** X2_corr 0.2511 0.1061 2.368 0.0287 * --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 0.06619 on 19 degrees of freedom Multiple R-squared: 0.9167, Adjusted R-squared: 0.908 F-statistic: 104.6 on 2 and 19 DF, p-value: 5.544e-11 > > (b1 <- (sd(Y)/sd(X1))*coef(dwaine.stdreg)[1]) # Compute b1 from b1* X1_corr 1.45456 > (b2 <- (sd(Y)/sd(X2))*coef(dwaine.stdreg)[2]) # Compute b2 from b2* X2_corr 9.3655 > (b0 <- mean(Y) - b1*mean(X1) - b2*mean(X2)) # Comute b0 X1_corr -68.85707 > > dwaine.reg <- lm(Y ~ X1 + X2) # Regression of Y on X1,X2 > summary(dwaine.reg) Call: lm(formula = Y ~ X1 + X2) Residuals: Min 1Q Median 3Q Max -18.4239 -6.2161 0.7449 9.4356 20.2151 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) -68.8571 60.0170 -1.147 0.2663 X1 1.4546 0.2118 6.868 2e-06 *** X2 9.3655 4.0640 2.305 0.0333 * --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 11.01 on 18 degrees of freedom Multiple R-squared: 0.9167, Adjusted R-squared: 0.9075 F-statistic: 99.1 on 2 and 18 DF, p-value: 1.921e-10 >