Abstract
Consider a model y i = β0 + β1 x i1 + β2 x i2 + e i , i = 1,…, n, with two explanatory variables. The synergy phenomenon deals with the case when . It is shown here that in the model with the regression vectors x 1 = (x 11,…, x n1)′ and x 2 = (x 12,…, x n2)′ such a phenomenon does not appear for all possible observation vectors y = (y 1,…, y n )′, if and only if or 1.
Mathematics Subject Classification: