Some people search the Internet for a set of topics and then use the number of search results ("hits") for each topic to rank the relative popularity of the topics. At the 2011 Joint Statistical Meetings (JSM), I had the opportunity to attend several talks by statisticians from Google and
I've previously described ways to solve systems of linear equations, A*b = c. While discussing the relative merits of the solving a system for a particular right hand side versus solving for the inverse matrix, I made the assertion that it is faster to solve a particular system than it
This is your chance to be a part of what has made SAS Global Forum a focal point of innovation in the SAS community for more than three decades. Now through November 14, paper submissions are being considered in the technology and industry solutions tracks. It’s time to write up
I'm currently enjoying the Australian "winter" as I travel around the region talking to SAS customers for the SAS Insight Series. It just so happens that I was in Perth, Western Australia for Australia's Census Night. Because I was in the country on this special day, I was compelled
On July 28, the weather wasn't the only thing that was hot in Richfield, Minnesota. About 130 SAS users from the Twin Cities area braved the heat to attend a sizzling summer meeting of the Twin Cities Area SAS Users Group (TCASUG). Meeting organizers Donalee Wanna and Brian Kreeger proclaimed
This article describes the SAS/IML CHOOSE function: how it works, how it doesn't work, and how to use it to make your SAS/IML programs more compact. In particular, the CHOOSE function has a potential "gotcha!" that you need to understand if you want your program to perform as expected. What
When I was at the Joint Statistical Meetings (JSM) last week, a SAS customer asked me whether it was possible to use the SGPLOT procedure to produce side-by-side bar charts. The answer is "yes" in SAS 9.3, thanks to the new GROUPDISPLAY= option on the VBAR and HBAR statements. For
The SAS/IML language provides two functions for solving a nonsingular nxn linear system A*x = c: The INV function numerically computes the inverse matrix, A-1. You can use this to solve for x: Ainv = inv(A); x = Ainv*c;. The SOLVE function numerically computes the particular solution, x, for a
Contributed by Debbi Scheufler and Kelley Weston MWSUG 2011 Conference Chairs ~ MWSUG 2011 planning is coming together quite nicely. We have a great line-up of formal and informal presentations and discussions, posters, workshops and social activities planned for Sunday through Tuesday, September 25 – 27. There should be something
In the SAS/IML language, the index creation operator (:) is used to construct a sequence of integer values. For example, the expression 1:7 creates a row vector with seven elements: 1, 2, ..., 7. It is important to know the precedence of matrix operators. When I was in grade school,
Contributed by Chris Decker, US Regional Director for PhUSE ~ PhUSE will be holding three Single Day Events between now and September 14 for pharmaceutical software users. PhUSE, (Pharmaceutical Users Software Exchange) began in 2005 in Europe to provide pharmaceutical software users with an environment where they could create and
Contributed by Ginger Carey and Kathy Valdés, WUSS 2011 Conference Chairs ~ The annual WUSS conference brings hundreds of SAS users and SAS experts together. Whether you are new to the world of SAS or have been using it for years, consider the benefits of attending WUSS 2011 in San
I've previously discussed how to find the root of a univariate function. This article describes how to find the root (zero) of a function of several variables by using Newton's method. There have been many papers, books, and dissertations written on the topic of root-finding, so why am I blogging
At the SAS/IML Support Community, a SAS/IML programmer recently asked how to find "the root of a complicated equation." That's a huge question, and many papers and books have been written on the topic of root-finding, also known as finding the zeros of a function. Everyone has favorite techniques for
One of the great innovations with SAS 9.3 is the focus on ODS statistical graphics. "Wait a minute," you're thinking, "weren't ODS graphics added in SAS 9.2?" Yes, that's true. But with SAS 9.3 there is even more capability: more analytical SAS procedures support the graphs, and there are more
A matrix is an array of numbers or character strings. When I print a matrix, I usually want to see only the data. However, sometimes it is helpful to add row or column headings that indicate the names of variables or labels for rows. A simple example is count data
In a previous blog post, I showed how to use the LOGISTIC procedure to construct a receiver operator characteristic (ROC) curve in SAS. That same day, Charlie H. blogged about how to use the DATA step to construct an ROC curve from basic principles. It has been a long time
I've written about how to add a diagonal line to a scatter plot by using the SGPLOT procedure in SAS 9.2. The main idea (use the VECTOR statement) is easy enough, but writing a program that handles a line with any slope requires some additional effort. But now SAS 9.3
The other day I needed to compute the signum function for each element of a matrix. If x is a real number, then the sgn(x) is -1 when x<0, 1 when x>0, and 0 when x=0. I wrote a SAS/IML module that contains a compact little expression: proc iml; start
I recently blogged about how many times, on average, you must roll a die until you see all six faces. This question is a special case of the coupon collector's problem. My son noted that the expected value (the mean number of rolls) is not necessarily the best statistic to
"Dad? How many times do I have to roll a die until all six sides appear?" I stopped what I was doing to consider my son's question. Although I could figure out the answer mathematically, sometimes experiments are more powerful than math equations for showing how probability works. "Why don't
Yesterday, Jiangtang Hu did a frequency analysis of my blog posts and noticed that there are some holidays on which I post to my blog and others on which I do not. The explanation is simple: I post on Mondays, Wednesdays, and Fridays, provided that SAS Institute (World Headquarters) is
Dates and times. As Wayne Finley states in his SUGI25 paper on SAS date and time handling, "The SAS system provides a plethora of methods to handle date and time values." Along with the plethora of methods is a plethora of papers on the topic. If you want to trick
I feel privileged to have been invited back to meet with SAS customers throughout New Zealand and Australia. I also feel lucky to escape the North Carolina summer (with temperatures trending in the 90s Fahrenheit) in exchange for the "winter" weather Down Under. For a good chunk of August, I'll
Tuesday's release of SAS 9.3 included the new SAS Forecast Server 4.1, which has several valuable enhancements: Combination (Ensemble) Models: A combination of forecasts using different forecasting techniques can outperform forecasts produced by using any single technique. Users can combine forecasts produced by many different models using several different combination
Welcome, SAS 9.3! I've already blogged about some interface and graphical changes that everyone should know about. Now I'll put on my statistical hat and mention a few 9.3 features that excite me, personally, as a data analyst and a statistical programmer: As a statistician, I am keen to try
Rick Wicklin created his own list of Five Interface and Graphics Features that Everyone Can Use. It's a very good summary of what you'll immediately notice when you use analytics procedures in SAS display manager: cool graphs turned on by default. For SAS Enterprise Guide users, you won't see such
Most of us grew up playing some type of sport and dreaming of becoming a collegiate or professional athlete. For me, it was a focus on dance and striving to be a professional ballerina. At some point we realized that in order to make this dream a reality, we’d have
Here are a few new interface and graphics changes that every SAS programmer should know about SAS 9.3: HTML is now the default output destination when you run the SAS windowing environment. This means that tables and graphs appear in an HTML document instead of the classic LISTING destination. Of
As I was reviewing notes for my course "Data Simulation for Evaluating Statistical Methods in SAS," I realized that I haven't blogged about simulating categorical data in SAS. This article corrects that oversight. An Easy Way and a Harder Way SAS software makes it easy to sample from discrete "named"
