how to determine which model is most correct if a variable is very non normal can it be a virf can pca affect input variable can you use pca on variables when calculating model can you use a pca to transform input variables? does pca factor change vif how can i tell which model is the most right why are residuals skewed what is vif and standard error do i need to worry about vif in multicollinearity if input variables are normal, which variable is normal if input variable is non normal do you need to worry what is the pca value of a vif in a micro model why do you use pca or vif when your model is very skewed can you use pca on a vif do pca'd variables affect vifs why is input variable extremely highly skewed why are vifs very high in ols when to worry about pca in input models how to calculate residuals from a model