Leonard A. Stefanski

Alumni Distinguished Professor Department of Statistics, North Carolina State University, Raleigh, NC, 27695-8203. len_stefanski@ncsu.edu Tel: (919) 515-1945 Fax: (919) 515-1169

COVID-19 Stress-Relieving Exercises and Inspirations

Endorphine-Releasing Exercise Video

When you start thinking that life in the COVID-19 era is an endless repetitive struggle, consider the fate of Sisyphus who was condemned by the Gods to repeatedly push a rock up a hill for all eternity ... and keep in mind that The struggle itself toward the heights is enough to fill a man's heart --- Albert Camus.

215 Influential Developments in Statistics Deconvolution made the list!

Measurement Error Models and Happiness SIMEX Increases Coefficient of Happiness!

Residual Plots   as described in   The American Statistician : Residual (Sur)Realism

Homer Simpson. Mathematics is no stranger to the Simpsons, see simpsonsmath.com, but this may be the first time that Homer has dabbled in statistics. It appears that he has embedded himself into an infinite do loop! The image above is a spoof of a scene from a Simpson's episode in which Homer tackles a difficult mathematical derivation. Click on the image to learn how it was constructed.

Gertrude Mary Cox (1900 - 1978). In 1940 Cox was appointed Professor of Statistics at NC State College (now NC State University). She established the Department of Experimental Statistics at NC State in 1941, the Institute of Statistics in 1944, and the Department of Mathematical Statistics at the University of North Carolina, Chapel Hill in 1946. Having received my PhD from the latter department, I can say with conviction (but not without controversy) that she saved her best work for last☺. Click on the image to learn how it was constructed.

Below is an animated illustration of a nifty feature available in the new version of JMP software---interactive tuning parameter selection for variable selection methods. The top-right panel contains the forward-selection, BIC criterion selection curve for a data set with the Homer Simpson image embedded in the residual plot (n = 8406, p = 99, 4 nonzero). As the tuning parameter moves right to left toward the minimum of BIC curve, the corresponding parameter estimates can be tracked on the coefficent path plots (top-left panel); and the resulting residual plots appear in the lower-left panel. Thanks to JMP developer and die-hard Wolfpack fan, Clay Barker, for preparing the animation. Read more about Clay's JMP interactive model building routines.

Projections can be revealing or misleading. The shadow art below by Shigeo Fukuda is made of 848 welded knives, spoons, and forks (the kind you eat with, not the front forks of a motorcycle). It is titled Lunch with a Helmet On. See more examples of shadow art. Thanks to Munir Winkel for bringing this to my attention.

Another article of interest from The American Statistician: The North Carolina Lottery Coincidence ...

The shadowy images you see around in the background are large trout holding in about six feet of water.

R Programs for Visualizing the NRC Rankings Data NRC Rankings Data.