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.
My 2018 SAS Global Forum paper was about "how to use the random-number generators (RNGs) in SAS." You can read the paper for details, but I recently recorded a short video that summarizes the main ideas in the paper. In particular, the video gives an overview of the new RNGs
If you use PROC SGPLOT to create ODS graphics, "ATTRS" are everywhere. ATTRS is an abbreviation of "attributes." Most options that change the attributes of a graphical element end with the ATTRS suffix. For example, the MARKERATTRS option modifies attributes of markers, the LINEATTRS option modifies attributes of lines, and
In SAS, the reserved keyword _NULL_ specifies a SAS data set that has no observations and no variables. When you specify _NULL_ as the name of an output data set, the output is not written. The _NULL_ data set is often used when you want to execute DATA step code
I recently recorded a short video about the new syntax for specifying and manipulating lists in SAS/IML 14.3. This is a video of my Super Demo at SAS Global Forum 2018. The new syntax supports dynamic arrays, associative arrays ("named lists"), and hierarchical data structures such as lists of lists.
The SURVEYSELECT procedure in SAS 9.4M5 supports the OUTRANDOM option, which causes the selected items in a simple random sample to be randomly permuted after they are selected. This article describes several statistical tasks that benefit from this option, including simulating card games, randomly permuting observations in a DATA step,
Years ago, I wrote an article about how to create a Top 10 table and bar chart. The program can be trivially modified to create a "Top N" table and plot, such as Top 5, Top 20, or even Top 100. Not long after the article was written, the developer
A previous article showed how to use a calibration plot to visualize the goodness-of-fit for a logistic regression model. It is common to overlay a scatter plot of the binary response on a predicted probability plot (below, left) and on a calibration plot (below, right): The SAS program that creates
The SAS language provides syntax that enables you to quickly specify a list of variables. SAS statements that accept variable lists include the KEEP and DROP statements, the ARRAY statement, and the OF operator for comma-separated arguments to some functions. You can also use variable lists on the VAR statements
This article shows how to construct a butterfly plot in SAS. A butterfly plot (also called a butterfly chart) is a comparative bar chart or histogram that displays the distribution of a variable for two subpopulations. A butterfly plot for the cholesterol readings of 5,057 patients in a medical study
In a recent blog post, Chris Hemedinger used a scatter plot to show the result of 100 coin tosses. Chris arranged the 100 results in a 10 x 10 grid, where the first 10 results were shown on the first row, the second 10 were shown on the second row, and so
