Suppose that you compute the coefficients of a polynomial regression by using a certain set of polynomial effects and that I compute coefficients for a different set of polynomial effects. Can I use my coefficients to find your coefficients? The answer is yes, and this article explains how. Standard Polynomial
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Let's face it: ever since cats learned how to access the Internet, they've managed to besmirch their prestigious status as the "smarter-if-a-bit-aloof" pet. They've starred in many demeaning YouTube videos, bringing shame to their species for the sake of some cheap laughs. But I'm here to tell you: there are
I just got back from a great conference in San Diego at the 2010 meeting of the Western Users of SAS Software (WUSS) where I gave several presentations on PROC IML and SAS/IML Studio. If you didn't make it to San Diego, you can still read my 2010 paper on
Sampling with replacement is a useful technique for simulations and for resampling from data. Over at the SAS/IML Discussion Forum, there was a recent question about how to use SAS/IML software to sample with replacement from a set of events. I have previously blogged about efficient sampling, but this topic
I recently returned from the 117th Annual Conference of the International Association of Chiefs of Police (IACP) held in Orlando, Florida. It was a tad surreal to be back with the association members and colleagues with whom I worked so closely for almost eight years when I called IACP my
Before the two most recent SAS Global Forums, I wrote posts introducing you to SAS presenters and SAS user presenters. In 2009 (my first SAS Global Forum), I wrote the SAS Presenters Series and introduced SAS professionals including I-Kong Fu, Chris Hemedinger and Daniel Jahn. In 2010, the introductions included
This post is about an estimate, but not the statistical kind. It also provides yet another example in which the arithmetic mean is not the appropriate measure for a computation. First, some background. Last week I read a blog post by Peter Flom that reminded me that it is wrong
Let's pretend for a moment that you don't have SAS installed on all of your office computers. But you've got some great content locked away inside SAS data sets. Is there a way to get to the content of that data, without having to push the data through a SAS
Increase the odds of winning for you and your company in 2011 by attending SAS Global Forum at Caesar’s Palace, April 4-7, in Las Vegas. For the past 36 years, this conference has attracted over 3,000 SAS users and over 400 SAS professionals from across the globe. It’s a sure
Today I'm in San Diego at the 2010 meeting of the Western Users of SAS Software (WUSS). I am giving several presentations on SAS/IML and SAS/IML Studio: A tutorial workshop on SAS/IML Studio for the SAS/STAT User. The material in this tutorial is a small sampling of Chapters 4–11 of
In this blog and in the book Statistical Programming with SAS/IML Software, I present tips and techniques for writing efficient SAS/IML programs for data analysis, simulation, matrix computations, and other topics of interest to statistical programmers. When I was writing my book, one of the reviewers commented that he wasn’t
Many forecasting software packages support hierarchical forecasting. You define the hierarchical relationship of your products and locations, create forecasts at one or more levels, and then reconcile the forecasts across the full hierarchy. In a top-down approach, you generate forecasts at the highest level and apportion it down to lower
How can you change a programming trick into a programming treat? Try this algorithm: If you develop a clever snippet of code, squirrel it away. This snippet is a "trick." If you use the trick a second time, copy and modify the code. The trick has become a "treat." If
Are you up to date on your hotfixes for SAS Enterprise Guide 4.1? If you're not certain of the answer, you'll find out next week when you might see this message appear: This version of SAS Enterprise Guide will expire on December 1st, 2010. If you've applied any SAS Enterprise
The SAS/IML language provides the QUAD function for evaluating one-dimensional integrals. You can also use the QUAD function to compute a double integral as an iterated integral. A One-Dimensional Integration Suppose you want to evaluate the following integral: To evaluate this integral in the SAS/IML language: Define a function module
~Contributed by Sara Jones~ It’s October and there’s a chill in the air. In North Carolina that means State Fair time. Now, for those who are not from the U.S., or for those who are, but don’t live in “the South” -- you may not know what this means. Think
We've just pushed out the localized versions of the Getting Started with SAS Enterprise Guide 4.3 tutorial. This is the tutorial that you'll see when you select Help->Getting Started Tutorial from within SAS Enterprise Guide. Here is a list of the supported languages, and links to the tutorial content: English
I was recently asked how to create a tridiagonal matrix in SAS/IML software. For example, how can you easily specify the following symmetric tridiagonal matrix without typing all of the zeros? proc iml; m = {1 6 0 0 0, 6 2 7 0 0, 0 7 3 8 0,
The question came up on the SAS Enterprise Guide discussion forum: which do you prefer, List Report Wizard (PROC REPORT) or Summary Tables (PROC TABULATE)? And as with most SAS-related questions, the proper response is: "it depends." If you put these two PROCs in the ring with a Google Fight,
Facebook now uses technology to help detect instances of cyberbullying before it gets out of hand. I heard this report on CNN last week, and the Facebook spokesman described their detection techniques as "background technology that I can't really talk about." We don't know for certain what techniques Facebook employs
In a previous post, I discussed how to use the LOC function to eliminate loops over observations. Dale McLerran chimed in to remind me that another way to improve efficiency is to use subscript reduction operators. I ended my previous post by issuing a challenge: can you write an efficient
It's like I was saying earlier: when used for good, statistics can inform your sound decisions and opinions. But stats can be used to mislead, as well. LifeHacker.com offers some basic guidance on this subject. And what if you already have the numbers you want to share, but you want
I am not a statistician, but I love statistics. Statistics are facts, and when used for good, they are an important ingredient in sound decision making about almost any issue, whether it's about government policy or your personal behavior. The use of statistics has gone way beyond counting things, computing
Today is World Statistics Day, an event set up to "highlight the role of official statistics and the many achievements of the national statistical system." I want to commemorate World Statistics Day by celebrating the role of the US government in data collection and dissemination. Data analysis begins with data.
Perhaps the toughest time in anyone's life is when you have to put away a loved one because they've been possessed by the devil. Other than that, though, I've had a good week*. And my week turns even better today, as we all join hands to celebrate World Statistics Day.
The IMLPlus language has been available to SAS customers since 2002, but there are still many people who have never heard of it. What is IMLPlus? The documentation SAS/IML Studio for SAS/STAT Users says this about IMLPlus: The programming language in SAS/IML Studio, which is called IMLPlus, is an enhanced
Have you ever been stuck while trying to solve a scrambled-word puzzle? You stare and stare at the letters, but no word reveals itself? You are stumped. Stymied. I hope you didn't get stumped on the word puzzle I posted as an anniversary present for my wife. She breezed through
A few people asked me to explain the significance of the cartoon in the scrambled-word puzzle that I posted as an anniversary present for my wife. The cartoon refers to a famous experiment devised by Sir Ronald A. Fisher.
In a previous post, I discussed how to generate random permutations of N elements. But what if you want to systematically iterate through a list of ALL permutations of N elements? In the SAS DATA step you can use the ALLPERM subroutine in the SAS DATA step. For example, the
