why does ols simplify why does the ols estimator simplify as follows for a single regressor case? what is the matrix of variance why does the OLS estimator simplify as follows for the single regressor case why do ols estimators simplify as follows why does an ols simplify in the epsilum? does ols simplify as follows why does ols simplify as follows why does olis simplify in a single regressor case why does the ols estimator simplify as follows for the single regressor case? why does the OLS estimator simplify as follows why do OLS estimators simplify what is sigma vs error matrix why is the ols matrix the same why does the ols estimator simplify as follows? why does the OLS estimator simplify as a single regressor? what is the variance of the ols in an example why does the ols estimator simplify as follows for the single regressor case? why does the ols estimator simplify as follows? why is ols simplify