References/Notes/Attributions:
Source
Simulated data, with thanks to Albert Kim for pointing out that this was omitted, and supplying the data and man documentation page on Oct 19, 2017
References
James, G., Witten, D., Hastie, T., and Tibshirani, R. (2013) An Introduction to Statistical Learning with applications in R, www.StatLearning.com, Springer-Verlag, New York