OLS regression in matrix form
The regression line is specified as:
ݔߚ⋯ ଶݔଶߚ ଵݔଵߚ ߚൌߚ′ݔ ሻ ൌݔ|ݕሺܧ
Marginal effects in the linear regression model are the coefficients.
In multiple linear regression, the coefficients are calculated as:
ܾ ൌ ൫ݔ′ݔ൯ିଵሺݔ′ݕሻ
Assumptions of the OLS estimator:
o Exogeneity of regressors
o Homoscedasticity
o Uncorrelated observations