FRM一级模拟自测:Omitted variable bias

The proper selection of factors to include in an ordinary least squares estimation is critical to the accuracy of the result.When does omitted variable bias occur?
 
a.Omitted variable bias occurs when the omitted variable is correlated with the included regressor and is a determinant of the dependent variable.
 
b.Omitted variable bias occurs when the omitted variable is correlated with the included regressor but is not a determinant of the dependent variable.
 
c.Omitted variable bias occurs when the omitted variable is independent of the included regressor and is a determinant of the dependent variable.
 
d.Omitted variable bias occurs when the omitted variable is independent of the included regressor but is not a determinant of the dependent variable.

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