There are many techniques for generating random variates from a specified probability distribution such as the normal, exponential, or gamma distribution. However, one technique stands out because of its generality and simplicity: the inverse CDF sampling technique. If you know the cumulative distribution function (CDF) of a probability distribution, then
ODS graph styles provide users with an easy way to control things such as the colors and fonts used in a graph, freeing the user from having to specify these properties in their code. A lot of thought was given to picking colors that work well together, and look good. The
In a previous article I discussed how to bin univariate observations by using the BIN function, which was added to the SAS/IML language in SAS/IML 9.3. You can generalize that example and bin bivariate or multivariate data. Over two years ago I wrote a blog post on 2D binning in
You’ve probably caught on by now that I live in the DC-metro area and suffer daily through the misery of congestion. Before I even reach for my keys, I check for the latest information from regional transportation agencies, especially Metro, to devise my plan of attack. Going way beyond the
Die politische Steuerung hat einen ernsthaften Verlust an Zustimmung in der Bevölkerung zu verzeichnen: Die fortschreitende Abnahme der Wahlbeteiligung ist nur eine, wenngleich wohl die präsenteste, Auswirkung dieser Entwicklung. Zuweilen wird das schwindende Vertrauen von Bürgerinnen und Bürgern in die Politik mit einer grundsätzlichen Abnahme des allgemeinen politischen Interesses in
It is often useful to partition observations for a continuous variable into a small number of intervals, called bins. This familiar process occurs every time that you create a histogram, such as the one on the left. In SAS you can create this histogram by calling the UNIVARIATE procedure. Optionally,
Did you know that more than 30,000 Americans die in traffic accidents every year? Interestingly, the U.S. import of mangoes from Brazil is found to be highly correlated with this fatality rate, as shown in the graph below. But are mango imports a good indicator of the future traffic fatality
This week's SAS tip is from Lauren Haworth, Cynthia L. Zender, and Michele Burlew's book Output Delivery System: The Basics and Beyond. This example-driven book includes broad coverage of some of the best features of ODS. To learn more about the book and the authors, visit our Web catalog to read
To say that I'm excited about the SAS 9.4 release is an understatement! For example, did you know that in SAS 9.4, you can write SAS/Graph output directly to a Powerpoint slide?!? This is definitely an item that was on my "wish list," and will no doubt make life a
SAS Forecast Server (release 12.3) is now shipping, and includes the new SAS Time Series Studio GUI. Time Series Studio (TSS), was released as "experimental" last August in 12.1, and is now in production. TSS provides an additional interface in Forecast Server, for time series data mining, exploration, and data preparation.
Are you still using the old RANUNI, RANNOR, RANBIN, and other "RANXXX" functions to generate random numbers in SAS? If so, here are six reasons why you should switch from these older (1970s) algorithms to the newer (late 1990s) Mersenne-Twister algorithm, which is implemented in the RAND function. The newer
SAS 9.3 already has smooth (anti-aliased) lines in SAS/GRAPH device=png output, and in SAS 9.4 you will also get smooth lines in your device=gif output (and gif animations)! Woo-hoo!!! Here are a couple of simple examples to demonstrate: The first example is device=gif Proc Gmap output. If you look very closely, you'll notice that
Mercifully, we have reached the final installment of Q&A from the June 20 Foresight-SAS webinar, "Forecast Value Added: A Reality Check on Forecasting Practices." As a reminder, a recording of the webinar is available for on-demand review, and the Foresight article (upon which the webinar was based) is available for free
The DELETE procedure is probably the most well-known and most-used SAS procedure that isn't actually documented or officially supported. That is, that was the case before the release of SAS 9.4, when PROC DELETE returns with more features than ever -- including a production-quality status. In his SAS Global Forum
Tried, tested and true -- I’m sure you already practice some, if not all, of these efficient techniques to save resources. I recently shared these 10 techniques with the Wisconsin Illinois SAS users group in Milwaukee. The conference ran smoothly under the incredibly able guidance of Dr. LeRoy Bessler. I’ll
Jede Branche und jeder Fachbereich kann und wird von Analytics profitieren. Doch jeweils ein wenig anders. Wie Sie bislang ungenutzte Erkenntnispotenziale in ihren Datenbergen heben können, erfahren Sie am 11. und 12. September 2013 in Mannheim. Das SAS Forum 2013 ist nicht nur die größte, sondern auch die individuellste Konferenz
If you are looking to find a job in business forecasting, or trying to fill one, there are many online resources available: Professional Organizations Institute of Business Forecasting & Planning - Very active searchable list of currently available jobs in forecasting and planning, from entry level to executive. Employers post
Every programming language has an IF-THEN statement that branches according to whether a Boolean expression is true or false. In SAS, the IF-THEN (or IF-THEN/ELSE) statement evaluates an expression and braches according to whether the expression is nonzero (true) or zero (false). The basic syntax is if numeric-expression then do-computation;
Q: Is the MAPE of the naive forecast the basis for understanding the forecastability of the behavior? Or are there other more in depth ways to measure the forecastability of a behavior? MAPE of the naive forecast indicates the worst you should be able to forecast the behavior. You can
On the Web site for the book Statistical Programming with SAS/IML Software, I provide instructions on how to download the sample data sets and install them so that they can be used from within SAS/IML Studio. When I wrote the book I did not anticipate that SAS users might want
Inspired by the JMP blog - Statisticians: harbingers of doom?: Enjoy what's left of the International Year of Statistics -- while you still can.
Q: Company always try to forecast 12 or 24m ahead. Whether we should track accuracy of 1m/3m/ 6m or x month forecast, does that depend on lead time? How to determine out of these 12/24 months, which month should we track accuracy? Correct, forecast performance is usually evaluated against the
As I wrote in my previous post, a SAS customer noticed that he was getting some duplicate values when he used the RAND function to generate a large number of random uniform values on the interval [0,1]. He wanted to know if this result indicates a bug in the RAND
When I work on SAS projects that create lots of files as results, it's often a requirement that those files be organized in a certain folder structure. The exact structure depends on the project, but here's an example: /results |__ html |__ images |__ xls |__ data Before you can
David Loshin (@davidloshin) on naming conventions for naming things.
Q: What is a legitimate goal to expect from your FVA...5%, 10%? Q: How do we set Target FVA which Forecasters can drive towards? The appropriate goal is to do no worse than a naive model, that is FVA ≥ 0. Sometimes, especially over short periods of time, you may
Tossing dice is a simple and familiar process, yet it can illustrate deep and counterintuitive aspects of random numbers. For example, if you toss four identical six-sided dice, what is the probability that the faces are all distinct, as shown to the left? Many people would guess that the probability
Please enjoy a much-needed break from FVA Q&A with editor Len Tashman's preview of the Summer 2013 issue of Foresight: Enlightenment has been our guiding principle through this, our 30th issue of Foresight. Since the journal’s inception in 2005, our mission has been to help the forecasting profession come to
Many SAS Enterprise Guide users practically live in the Query Builder. For those who understand their data tables, the Query Builder provides a tremendous amount of flexibility to pull and manipulate data. The Query Builder produces SQL programs behind the scenes, which translates well for database-centric work. Sometimes a complex
With this Q&A Part 3, we are about halfway through the questions submitted during the FVA webinar. We did over 15 minutes of live Q&A at the end of the webinar, and covered many of the submitted questions at that time, however I always prefer to issue complete written responses to
