About this blog
Rick Wicklin, PhD, is a senior 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, statistical simulation, 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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The mosaic plot is a graphical visualization of a frequency table. In a previous post, I showed how to use the FREQ procedure to create a mosaic plot. This article shows how to create a mosaic plot by using the MOSAICPARM statement in the graph template language (GTL). (The MOSAICPARM [...]Post a Comment
Mosaic plots (Hartigan and Kleiner, 1981; Friendly, 1994, JASA) are used for exploratory data analysis of categorical data. Mosaic plots have been available for decades in SAS products such as JMP, SAS/INSIGHT, and SAS/IML Studio. However, not all SAS customers have access to these specialized products, so I am pleased [...]Post a Comment
If you’ve ever tried to use PROC FREQ to create a frequency table of two character variables, you know that by default the categories for each variable are displayed in alphabetical order. A different order is sometimes more useful. For example, consider the following two-way table for the smoking status [...]Post a Comment
A challenge for statistical programmers is getting data into the right form for analysis. For graphing or analyzing data, sometimes the “wide format” (each subject is represented by one row and many variables) is required, but other times the “long format” (observations for each subject span multiple rows) is more [...]Post a Comment
On Kaiser Fung’s Junk Charts blog, he showed a bar chart that was “published by Teach for America, touting its diversity.” Kaiser objected to the chart because the bar lengths did not accurately depict the proportions of the Teach for America corps members. The chart bothers me for another reason: [...]Post a Comment
In my last blog post I described how to implement a “runs test” in the SAS/IML language. The runs test determines whether a sequence of two values (for example, heads and tails) is likely to have been generated by random chance. This article describes two applications of the runs test. [...]Post a Comment
While walking in the woods, a statistician named Goldilocks wanders into a cottage and discovers three bears. The bears, being hungry, threaten to eat the young lady, but Goldilocks begs them to give her a chance to win her freedom. The bears agree. While Mama Bear and Papa Bear block [...]Post a Comment
SAS has supported calling R from the SAS/IML language since 2009. The interface to R is part of the SAS/IML language. However, there have been so many versions of SAS and R since 2009, that it is hard to remember which SAS release supports which versions of R. The following [...]Post a Comment
A common visualization is to compare characteristics of two groups. This article emphasizes two tips that will help make the comparison clear. First, consider graphing the differences between the groups. Second, in any plot that has a categorical axis, sort the categories by a meaningful quantity. This article is motivated [...]Post a Comment
Earlier this week I posted a “guest blog” in which my 8th grade son described a visualization of data for the 2013 ASA Poster Competition. The purpose of today’s blog post is to present a higher-level statistical analysis of the same data. I will use a t test and a [...]Post a Comment