Rick Wicklin
Rick Wicklin RSS
Research Statistician Developer

Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of PROC IML and SAS/IML Studio. His areas of expertise include computational statistics, 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. Follow @RickWicklin on Twitter.

Recent Posts

Lexicographic combinations in SAS

In a previous blog post, I described how to generate combinations in SAS by using the ALLCOMB function in SAS/IML software. The ALLCOMB function in ... Read More

Computing prediction ellipses from a covariance matrix

In a previous blog post, I showed how to overlay a prediction ellipse on a scatter plot in SAS by using the ELLIPSE statement in ... Read More

Add a prediction ellipse to a scatter plot in SAS

It is common in statistical graphics to overlay a prediction ellipse on a scatter plot. This article describes two easy ways to overlay prediction ellipses ... Read More

How to create and detect an empty matrix

An empty matrix is a matrix that has zero rows and zero columns. At first "empty matrix" sounds like an oxymoron, but when programming in ... Read More

The SAS/IML File Exchange is open

Have you written a SAS/IML program that you think is particularly clever? Are you the proud author of SAS/IML functions that extend the functionality of ... Read More

A log transformation of positive and negative values

In my four years of blogging, the post that has generated the most comments is "How to handle negative values in log transformations." Many people ... Read More

Create custom tick marks for axes on the log scale

In my previous blog post, I showed how to use log axes on a scatter plot in SAS to better visualize data that range over ... Read More

Scatter plots with logarithmic axes...and how to handle zeros in the data

If you are trying to visualize numerical data that range over several magnitudes, conventional wisdom says that a log transformation of the data can often ... Read More

An easy way to expand data by using frequencies

A few years ago I blogged about how to expand a data set by using a frequency variable. The DATA step in the article was ... Read More

Pairwise comparisons of a data vector

A SAS customer showed me a SAS/IML program that he had obtained from a book. The program was taking a long time to run on ... Read More