Hi all r-mailling listers: Can anyone explain the theory (or the formula) about computing Sum Sq (color highligh below) related to regression items? The link of Wikipedia ( http://en.wikipedia.org/wiki/Partition_of_sums_of_squares) gives an introduction on how to calculate the total, model, and regression sum of squares. Is it similar to the Sum Sq computation? Is the regression sum of squares equal to (0.000437+ 0.002545+ 0.060984+ 0.062330+ 0.060480)? Any suggestion will be greatly appreciated. Thank you! David TraingData<-data.frame( x1=c(3.532,2.868,2.868,3.532,2.868,2.536,3.864), x2=c(1.992,1.992,1.328,1.328,1.328,1.66,1.66), y=c(9.040330254,8.900894412,8.701929163,9.057944749,8.701929163,8.74317832,9.10859913) ) lm.sol<-lm(y~1+x1+x2+I(x1^2)+I(x2^2)+I(x1*x2),data=TraingData) anova(lm.sol) Analysis of Variance Table Response: y Df *Sum Sq* Mean Sq F value Pr(>F) x1 1 0.000437 0.000437 0.1055 0.8001 x2 1 0.002545 0.002545 0.6141 0.5768 I(x1^2) 1 0.060984 0.060984 14.7162 0.1623 I(x2^2) 1 0.062330 0.062330 15.0409 0.1607 I(x1 * x2) 1 0.060480 0.060480 14.5945 0.1630 Residuals 1 0.004144 0.004144 [[alternative HTML version deleted]]