[R] basic question: Linear model

Hey, I try to understand a basic statistic question. I am modelling a linear regression Y=X*B+E. To compute the effect of “group” the B-values of the regressors/columns that code the interaction effects (col. 5-8 and col. 11-14, see below) have to be weighted with non-zero elements within the

[R] Linear model: contrasts

Hey, I am modelling a linear regression Y=X*B+E. To compute the effect of “group” the B-values of the regressors/columns that code the interaction effects (col. 5-8 and col. 11-14, see below) have to be weighted with non-zero elements within the contrast Group 1 minus Group 2 (see below). My