By Including Another Variable in the Regression,you Will

Multiple Choice

By including another variable in the regression,you will

A) decrease the regression R2 if that variable is important.
B) eliminate the possibility of omitted variable bias from excluding that variable.
C) look at the t-statistic of the coefficient of that variable and include the variable only if the coefficient is statistically significant at the 1% level.
D) decrease the variance of the estimator of the coefficients of interest.