why does an omitted variable biased the coefficients which criterion is used to select a model why is it useful to omitted variable what happens in a model selection procedure why would one always use a model selection procedure how to find out if an omitted regressor is biased if a coefficient is omitted, what is the resulting effect why is a model selection procedure used why omitted regressor is a criterion in model selection how can you tell if a model is biased using an omitted variable? how to check if a model is biased why a model selection procedure is used when a model identifies an error term, the model selection procedure is called what is the importance of model selection procedure what is the purpose of a model selection procedure which criterion is most commonly used to evaluate a model for bias? what to check if a model is biased what makes a selection procedure biased when a variable gets omitted why is a regressor kicked out of a test why are models chosen by their criterion