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.
Weighted averages are all around us. Teachers use weighted averages to assign a test more weight than a quiz. Schools use weighted averages to compute grade-point averages. Financial companies compute the return on a portfolio as a weighted average of the component assets. Financial charts show (linearly) weighted moving averages
I wrote 114 posts for The DO Loop blog in 2015. Which were the most popular with readers? In general, highly technical articles appeal to only a small group of readers, whereas less technical articles appeal to a larger audience. Consequently, many of my popular articles were related to data
Lo how a rose e'er blooming From tender stem hath sprung As I write this blog post, a radio station is playing Chrismas music. One of my favorite Christmas songs is the old German hymn that many of us know as "Lo, How a Rose E're Blooming." I was humming
The most recent development environment for SAS programmers is SAS Studio, which is a browser-based application. The free SAS University Edition, which includes SAS/IML software, also uses SAS Studio as a development environment. SAS Studio has a special mode for programmers who use interactive procedures such as PROC IML. (Recall
Recently Sanjay Matange blogged about how to color the bars of a histogram according to a gradient color ramp. Using the fact that bar charts and histograms look similar, he showed how to use PROC SGPLOT in SAS to plot a bar chart in which each bar is colored according
A SAS customer asked: Why isn't the chi-square distribution supported in PROC UNIVARIATE? That is an excellent question. I remember asking a similar question when I first started learning SAS. In addition to the chi-square distribution, I wondered why the UNIVARIATE procedure does not support the F distribution. These are
Last week my colleague Chris Hemedinger published a blog post that described how to use the ODS LAYOUT GRIDDED statement to arrange tables and graphs in a panel. The statement was introduced in SAS 9.4m1 (December 2013). Gridded layout is supported for HTML, POWERPOINT, and the PRINTER family of destinations
When creating a statistical graphic such as a line plot or a scatter plot, it is sometimes important to preserve the aspect ratio of the data. For example, if the ranges of the X and Y variables are equal, it can be useful to display the data in a square
A matrix is a convenient way to store an array of numbers. However, often you need to extract certain elements from a matrix. The SAS/IML language supports two ways to extract elements: by using subscripts or by using indices. Use subscripts when you are extracting a rectangular portion of a
Sometimes you are writing a program that needs to find out whether a particular SAS product (like SAS/ETS, SAS/QC, or SAS/OR) is licensed. I was reminded of this fact when I wrote last week's blog post about how to create a map with PROC SGPLOT. Although the SGPLOT procedure is
