Author

Rick Wicklin
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Distinguished Researcher in Computational Statistics

Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of SAS/IML software. His areas of expertise include computational statistics, simulation, statistical graphics, and modern methods in statistical data analysis. Rick is author of the books Statistical Programming with SAS/IML Software and Simulating Data with SAS.

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Rick Wicklin 0
Ways to multiply in the SAS/IML language

For programmers who are learning the SAS/IML language, it is sometimes confusing that there are two kinds of multiplication operators, whereas in the SAS DATA step there is only scalar multiplication. This article describes the multiplication operators in the SAS/IML language and how to use them to perform common tasks

Rick Wicklin 0
Compute confidence intervals for percentiles in SAS

PROC UNIVARIATE has provided confidence intervals for standard percentiles (quartiles) for eons. However, in SAS 9.3M2 (featuring the 12.1 analytical procedures) you can use a new feature in PROC UNIVARIATE to compute confidence intervals for a specified list of percentiles. To be clear, percentiles and quantiles are essentially the same

Rick Wicklin 0
The new book on my desk

In my constant effort to keep pace with Chris Hemedinger, I am pleased to announce the availability of my new book, Simulating Data with SAS. Chris started a tradition for SAS Press authors to post a photo of themselves with their new book. Thanks to everyone who helped with the

Rick Wicklin 0
The whys and hows of simulating data

When I told a friend that the title of my new book is Simulating Data with SAS, she asked, “Why would anyone want to simulate data?”  To her, data are measured or surveyed. Data tell us how big, how often, and how many.  Data indicate people’s opinions about politics and

Rick Wicklin 0
How to plot a discontinuous function

It is easy to use the SGPLOT procedure in SAS to plot the graph of a well-behaved continuous function: just create a data set of the (x,y) values on some domain and use the SERIES statement to connect the points. However, to plot the graph of a discontinuous function correctly

Rick Wicklin 0
IMLPlus documentation is now available online

I am pleased to announce that the documentation for the IMLPlus language is now available online. Previously, this resource was available only from within the SAS/IML Studio application. This documentation can now be accessed by anyone, regardless of whether they have installed SAS/IML Studio. As I have described previously, IMLPlus

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Rick Wicklin 0
How the J function got its name

In linear algebra, the I symbol is used to denote an n x n identity matrix. The symbol J (or sometimes 1) is used to denote an n x p matrix of ones. When the SAS/IML language was implemented, the I function was defined to generate the identity matrix. The J function was defined

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