Bootstrap methods and permutation tests are popular and powerful nonparametric methods for testing hypotheses and approximating the sampling distribution of a statistic. I have described a SAS/IML implementation of a bootstrap permutation test for matched pairs of data (an alternative to a matched-pair t test) in my paper "Modern Data
Whether you’re counting carbs for glucose management, crunching calories for weight loss or beefing up your protein intake to build muscle mass, food tracking apps can be an invaluable resource for your health and fitness goals. A novelty a few years ago, these apps are now in abundance giving us
A little-known but useful feature of SAS/IML 12.3 (which was released with SAS 9.4) is the ability to generate a vector of lowercase or uppercase letters by using the colon operator (:). Many SAS/IML programmers use the colon operator to generate a vector of sequential integers: proc iml; x =
So far in our Ask the Statistician blog and video series, we have heard responses from statisticians at the Analytics 2013 conference about: The many ways statistics benefit their organizations. The types of statistical analyses used to solve business issues. Best practices for explaining results. How they put statistical
I’ve recently had the opportunity to learn a little more about administering SAS Visual Analytics. The sessions introduced me to two new GUI interfaces that simplify the work for SAS administrators. In my last post, I shared how to load data into memory using the SAS Visual Data Builder. After
In a previous post, I stated that you should avoid matrix multiplication that involves a huge diagonal matrix because that operation can be carried out more efficiently. Here's another tip that sometimes improves the efficiency of matrix multiplication: use parentheses to prevent the creation of large matrices. Matrix multiplication is
Principle 7: Accuracy - Risk management reports should accurately and precisely convey aggregated risk data and reflect risk in an exact manner. Reports should be reconciled and validated. Successful demonstration of Principle 7 requires senior management to rely upon the information presented in risk reporting. Since forward-looking strategic decisions are
I love working with SAS Technical Support because I get to see real problems that SAS customers face as they use SAS/IML software. The other day I advised a customer how to improve the efficiency of a computation that involved multiplying large matrices. In this article I describe an important
Data federation is a relatively new term used to describe a form of data virtualization. Data virtualization, however, is not new. It has been around since at least the 1960's when virtual memory was introduced to simulate additional memory beyond what was physically available on a machine. While data federation is a
Imagine this scenario: Every device we encounter in our day-to-day routine – from our refrigerators and automobiles to our water and gas meters – has embedded sensors that read real-time information and generate unfathomable amounts of data. Now take this scenario one step further. Imagine what kinds of insights we’d
A recent Charlotte Observer article provided a thoughtful investigation of growth and achievement in North Carolina’s Charlotte Mecklenburg Schools). The article juxtaposed two very different, yet highly effective, schools. The first, Ranson Middle School, is a low-achieving school with 84% poverty that demonstrated the highest academic growth of any similar
In light of the recent reports that glaciers in Antarctica are melting, what SAS graphs might be useful in analyzing the data?... When floating sea ice melts (such as at the North Pole), it doesn't raise the sea level - but when ice on land melts (such as glaciers at
SAS administrators often ask for a utility that can detect orphaned SAS WORK and SAS Utility directories on their back-end SAS compute systems. These orphaned directories result when a SAS Enterprise Guide or any other SAS GUI application is terminated incorrectly, and the SAS session does not terminate properly. SAS
There has been lots of awareness-raising lately about the safety of our food supply including the tools we use to cook and store our food. Many nutritionists, health care providers and scientists agree that reducing exposure to toxins whenever possible makes good sense. The Environmental Working Group (EWG), an environmental
Last week, as part of an article on how spammers generate comments for blogs, I showed how to generate random messages by using the CATX function in the DATA step. In that example, the strings were scalar quantities, but you can also concatenate vectors of strings in the SAS/IML language.
What if you could rank where you stand versus your industry peers when it comes to how effectively you're making use of your data through analytics? Now you can. Jim Davis, Senior Vice President and Chief Marketing Officer at SAS, outlined an eight-metric test at today’s Premier Business Leadership Series
The US health care industry is always getting a bad rap. It takes heat for being too expensive or not efficient enough or just too complicated. We know we need it, and that living long and healthy lives requires it. But we also know we love to complain about it
This SAS tutorial video will show you how to generate plots for two continuous numeric variables with Base SAS. Basic scatter plots, linear or curvilinear regression lines, confidence intervals or ellipses, and multiple plot overlays are demonstrated. To learn more about this topic, check out our SAS Programming 1: Essentials
It was just a couple of years ago that folks were skeptical about the term "data scientist". It seemed like a simple re-branding of an established job role that carried titles such as "business analyst", "data manager", or "reporting specialist". But today, it seems that the definition of the "Data
In my recent post on how to understand character vectors in SAS/IML, I left out an important topic: How can you allocate a character vector of a specified length? In this article, "length" means the maximum number of characters in an element, not the number of elements in a vector.
In my previous post in the Ask the Statistician interview series, we heard from statisticians at the Analytics 2013 conference discuss the how their statistical results are put into action within their organizations. Now let’s learn more about their specific examples of success they have had utilizing these results. Check out
It’s an understatement to say there are many Base SAS procedures! Some procedures may be used for basic report writing. Other procedures may be used to perform statistical analysis. Some have similar functions. Others are unique in the output that they can produce. Which procedure you choose generally depends on
I'm currently working on a large project for a SAS customer. The project comprises many activities and phases, so there is a need to track progress on many different levels. During a recent meeting the project manager announced, "I'm putting together a status deck, and I'll include some Harvey Balls
Many years ago I was a SAS administrator for both a UNIX server and a LINUX server. I had a lot of syntax memorized and a lot of commands at my fingertips. If I ever mis-typed a command, I’d have to try again. I remember writing plenty of batch scripts
Last week Chris Hemedinger posted an article about spam that is sent to SAS blogs and discussed how anti-spam software helps to block spam. No algorithm can be 100% accurate at distinguishing spam from valid comments because of the inherent trade-off between specificity and sensitivity in any statistical test. Therefore,
All my friends seem to be having twins these days (below is a picture of my friend Holly's twins, for example) - I wondered if I could use SAS to analyze this twinning trend ... When I was growing up, way back in the day, twins seemed to be rarity.
All Analytics spoke with several leaders at the recent SAS Global Forum Executive Conference on what it means to build an analytics culture. Here’s a video of those conversations. The video features several sections related to building an analytics culture: Kim Nevala, Director of Business Strategy for the SAS Best
SAS programmers are probably familiar with how SAS stores a character variable in a data set, but how is a character vector stored in the SAS/IML language? Recall that a character variable is stored by using a fixed-width storage structure. In the SAS DATA step, the maximum number of characters
I'm an avid Star Wars fan, and am cautiously optimistic about what J.J. Abrams intends to do in Star Wars VII. The cast for the movie was revealed earlier this week, and today is May the Fourth, an unofficial Star Wars holiday. You might be asking yourself what any of
SG Procedures and GTL provide you with a large set of plot statements, such as BarChart, ScatterPlot, BoxPlot and more. You can use them for the intended purpose, and all is well and good. However, the real fun starts when you leverage a plot to do something that was not
