Question

4 Variance-Covariance Matrix of the OLS Estima- tor The fourth classical assumption is about the covariance matrix of the random error term: V(u X) = E uu x)= oʻI, How'we derived it?(uu^T) This assumption implies that the error terms are incorrelated and homoscedastic. Let us take a closer look at the covariance matrix. Note that all expectations are conditional on X: E(uu) = E 1 [u U2 ... Un u Juu = ET uu ... un u ... Uzun Why these are not 02 [ E(u) E(uzui) (uus) ... Eſuun) E(uz) ... E(uzun) (2) E(unui) E(Unus) ... 20 ... 0 0 02 ... 0 00... 02

Answer 1

124 In OLs method of estimation, we have বিদ্যালয় শিক্ষা দপ্তর yaxßre where did not No vo vek) 6 In here, uld, Elk) LE(E)" «E(&)2 5. In, [E(E)= o) - Fly? FCę). Esſe &z [w]) Elek) Tela) 6(86) -- Lace ) 5(85&w) - --fle