Provides index plots of Cook's distances, leverages (hat values), Studentized residuals, and outlier significance levels for a regression object.

## Details

Roughly, in a model with *n* samples and *p* predictors (including the intercept), studentized residuals larger than 2 indicate possible outliers, hat values larger than 2**p*/*n* indicate possible high leverage values, and Cook's distance values larger than 4/(*n*-*p*) indicate possible highly influential observations.

## Acknowledgements

Uses the `influenceIndexPlot` function from the `car` package.

## References

Fox, J., & Sanford, W. (2011). An R Companion to Applied Regression, Second Edition. Thousand Oaks CA: Sage.

Weisberg, S. (2014). Applied Linear Regression, Fourth Edition. Wiley.