I have previously blogged about how to convert a covariance matrix into a correlation matrix in SAS (and the other way around). However, I still get questions about it, perhaps because my previous post demonstrated more than one way to accomplish each transformation. To eliminate all confusion, the following SAS/IML
English
The graph showing the distribution of the maximum liver function test values by treatment for all participants in a study is commonly used for the analysis of safety data in clinical trials. The data is often structured in multiple columns (one per treatment) as below on the left, or grouped by
Bank Systems & Technology just published a special issue focused on "big data" - and how high-performance analytics helps solve the big data problem. Clicking on the cover image will take you to the ebook, so you can flip through 24 pages full of information about the benefits of big data for banking.
I previously described how to use Mahalanobis distance to find outliers in multivariate data. This article takes a closer look at Mahalanobis distance. A subsequent article will describe how you can compute Mahalanobis distance. Distance in standard units In statistics, we sometimes measure "nearness" or "farness" in terms of the
Do you love SAS? I do! And there is a special place for me to share that love. Don't worry there is a special place for you, too. It just so happens that it is the same place – SAS users groups. SAS users groups hold events to allow attendees
So, there’s a lot of talk about staying for the magic of Disney World after SAS Global Forum. What about arriving early for some SAS magic? A selection of some of the most popular SAS training courses is being offered Wednesday – Friday, April 18-20 prior to the conference. Here’s
How we love shortcuts. Our life seems more efficient with them. I try to take the earlier train for a good parking spot that lets me exit early. Actually change that to any spot (my train station has tons of commuters with FEW parking spaces so getting up early is the
The Walt Disney World Swan and Dolphin Resort (the headquarters hotel) is offering a great rate to SAS Global Forum attendees. This amazing facility is where all of the action is. No cars to rent, no gas tanks to fill. No parking to find and pay for – which means no searching
Way back when I learned to program, I remember a computer instructor explaining that an IF-THEN statement can be a relatively slow operation. He said "If a multiplication takes one unit of time, an IF statement requires about 70 units." I don't know where his numbers came from, or even
The parable of beer and diapers is often related when teaching data mining techniques. Whether fact or fiction, a Heat Map is useful to view the claimed associations. A co-worker recently enquired about possible ways to display associations or dependency between variables. One option is to show the dependency as a node
I have a love-hate relationship with spreadsheet data. I am interested in finding data to analyze, and if it arrives in the form of a spreadsheet, I'll take it. And I like to deliver results and reports, but often my constituents ask for it as a spreadsheet that they can
Big data is one of the hottest topics in business. When you hear those words - BIG Data - you almost surely think of: HUGE financial services firms scoring terabytes of historical and current risk data GLOBAL telecommunications companies mining petabytes of structured and unstructured data INTERNATIONAL retailers repricing hundreds of thousands of products across
The American Association of State Highway Transportation Officials recently released a top 10 list of transportation issues that will be “talked, written or tweeted and legislated about” in 2012. As expected, funding constraints and Congressional action on reauthorization appear on the list but the group also notes that natural disaster
Unlike prior versions of SAS OLAP technology, 9.2 provides more options for maintaining and refreshing OLAP cubes. With this comes some discussion about what each one does alone, and how pairing these techniques really provides SAS OLAP Server Administrators and cube developers a cornucopia of OLAP options. PROC OLAPOPERATE Remember
Here is the second installment of sample graphs from the SG Procedures book - The Adverse Event Timeline. This is a graph commonly used in patient profiles for clinical trials where we track the progress of a patient through a hospitalization event, tracking the dates and severity of the adverse events. The
A variance-covariance matrix expresses linear relationships between variables. Given the covariances between variables, did you know that you can write down an invertible linear transformation that "uncorrelates" the variables? Conversely, you can transform a set of uncorrelated variables into variables with given covariances. The transformation that works this magic is
Many of the chapters in my new book Building Business Intelligence Using SAS: Content Development Examples were straightforward to write but one in particular was the beast. Neither Tricia nor I wanted to tackle the SAS BI Dashboard chapter. Just chalk it up to no major work experience with this
Have you ever wanted to run a sample program from the SAS documentation or wanted to use a data set that appears in the SAS documentation? You can: all programs and data sets in the documentation are distributed with SAS, you just have to know where to look! Sample data
Recently a user posted a question on the SAS/GRAPH and ODS Graphics Communities page on how to plot the normal density curves for two classification levels in the same graph. We have often seen examples of a distribution plot of one variable using a histogram with normal and kernel density curves. Here is a simple example: Code Snippet:
Sara started it, and I like the idea - the Unofficial Official Guide to SAS Global Forum. My contribution to this unofficial guide is “The Agenda Builder and why it matters to me." In case you're wondering, I use it to:
My colleague, Steve Serrao, just published a blog post on the proliferation of varied law enforcement approaches and their related phraseologies. After reading, I concur – hence, this blog’s title. I am not a huge fan of the term “predictive policing”. While others may love it and live it, and
We call it the "metadata profile", but really it's like a telephone number that connects you to your SAS environment. Just as a telephone number has component parts (country code, area code, exchange), the metadata profile contains information that allow you to "dial in" to your SAS servers. This information
In two previous blog posts I worked through examples in the survey article, "Robust statistics for outlier detection," by Peter Rousseeuw and Mia Hubert. Robust estimates of location in a univariate setting are well-known, with the median statistic being the classical example. Robust estimates of scale are less well-known, with
In December of last year, the book "Statistical Graphics Procedures by Example" co-authored by Dan Heath and I was published. On the back cover, it proclaims "Free Code on the Web". Now, who can resist such an offer? Since most of the examples in the book have very short syntax,
Recently I've made several online purchases buying eBooks for the new Amazon Kindle my daughter received as a holiday gift. The online checkout process is very straight-forward, especially with the 'Continue' buttons that change to a 'Place your order' button on the final step. Did you know that the same
Everyone is looking for a bargain, especially those traveling with their families to Orlando for SAS Global Forum. Orlando is the land of theme parks and attractions, many with hefty ticket prices. Since I am heading to Orlando in April myself, I have been doing quite a lot of research.
The other day I encountered the following SAS DATA step for generating three normally distributed variables. Study it, and see if you can discover what is unnecessary (and misleading!) about this program: data points; drop i; do i=1 to 10; x=rannor(34343); y=rannor(12345); z=rannor(54321); output; end; run; The program creates the
Recently, I had a discussion with a user concerning the volume of imagemap data generated for an interactive, web-based visual contain a large number of graphs. The large amount of imagemap data was causing problems with the current version of their web browser. The graphs consisted of either bar charts
So many of us struggle with this mountain. In fact, 68.27% of us get within sight of reaching the summit (while 95.47% of us are at least on a perceivable slope). We run, walk, crawl and sometimes slide our way uphill (from one direction or the other) until we finally
When developing content in SAS BI Dashboard, such as indicators, ranges, and dashboards, knowing how to name them is pretty important. If changes are required later (for instance to improve the administrators capability of partial promoting content) much more work is required to ensure the links between the objects isn't