Write Down, in General, the Variance-Covariance Matrix for the Multiple $\sigma _ { \mathrm { u } } ^ { 2 }$

question 17

Essay

Write down, in general, the variance-covariance matrix for the multiple regression error term U. Using the assumptions cov(ui,uj|XiXj)= 0 and var(ui|Xi)= $\sigma _ { \mathrm { u } } ^ { 2 }$ Show that the variance-covariance matrix can be written as $\sigma _ { \mathrm { u } } ^ { 2 }$ I_n.

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Definitions:

Renal Artery

A blood vessel that supplies oxygenated blood to the kidneys.

Suprarenal Artery

Blood vessels that supply blood to the adrenal glands located above the kidneys.

Femoral Artery

A major artery in the thigh that supplies oxygenated blood to the lower part of the body.

Celiac Trunk

A major artery that supplies blood to the stomach, spleen, liver, and other parts of the abdomen.