Variance, Covariance Matrix, Linear Regression, Standard Error, Confidence Interval.
Assumptions (4) and (5) only describe the behavior of the variances of the model’s errors. Although, assumptions (1) through (5) together lead up to the formulation of the linear OLS regression model’s variance-covariance matrix, if (1) through (3) are satisfied but (4) and /or (5) are not, the