In order to understand the correct situation in which to use the word affect or effect, the first thing one must do is have a clear understanding of what each word means. 1  Affect is usually used as a verb. It is an action word that means to produce a change in or influence something. 2  Effect is usually used as a noun.
Shear Factor. The distance a point moves due to shear divided by the perpendicular distance of a point from the invariant line.
Variance Inflation factor. I need to calculate VIF (variance inflation factor) for my linear regression model. I found there was a function named vif in 'HH' package. 1) I was able to install that package in my R under windows. Package HH is not available.