# Multiple Regression

- Using more than one explanatory variable in a regression model
- Y = b
_{0}+ b_{1}X_{1}+ b_{2}X_{2}+ b_{3}X_{3}+ u_{I}

- Y = b
- Omitted variable bias
- The biasness incurred due to omission of one or more explanatory variable from the model.

- Omitted variable bias occurs when two conditions are met:
- Omitted variables are correlated with the independent variable
- Variables that are not accounted for in the model but affect the dependent variable