Wednesday, August 17, 2011

Interactive Statistics - Wolfram's CDF format

Many of you will be familiar with Wolfram Research, the company that delivers Mathematica, among other things. Last month, they launched their new Computable Document Format (CDF) - it's something I'm going to be using a lot in my undergraduate Economic Statistics course.

Here are a few words taken from their press release of July 21:

'Wolfram Research today announced the Computable Document Format (CDF), a new standard to put interactivity at the core of everyday documents and empower readers with live content they can drive.

Traditional documents are easy to author, but are limited to content that's static or can only be played back. Interactivity is familiar in apps, but usually requires programmers to create, rarely making it cost-effective for communicating ideas. As a result, today's content lacks interactivity to engage with-dramatically limiting readers' understanding.

By contrast, CDFs are as interactive as apps, yet as everyday as documents. Central to the concept are knowledge apps, interactive diagrams, or info apps-the live successors of traditional diagrams and infographics.

"Today it's inconceivable that textbooks, financial reports, or news articles wouldn't include visuals; they're too valuable to communicating the idea," said Conrad Wolfram, Director of Strategic Development at Wolfram Research. "Tomorrow, communicating ideas without interactivity will be just as inconceivable. CDF is here to make that change." Wolfram added, "If a picture is worth a thousand words, an interactive knowledge app is worth a thousand pictures. CDF steps up the bandwidth of communication that much."

CDF is a computation-powered knowledge container. Its interactivity isn't just pre-generated, but live. And for the first time, authoring typically doesn't need professional programmers, but is easy enough for teachers, journalists, analysts, managers, or researchers to themselves create the knowledge or info apps or interactive diagrams for reports and presentations, articles, and textbooks.'

Once you download and install the free CDF Player from here, you're immediately in business. You can get an idea of what CDF is all about, and its potential for teaching and reporting statistical and econometric-related material by playing with some of the applications on the Wolfram Demonstration Project web page.

A few good starting points are the apps. for illustrating confidence intervals; the t-test for the mean of a normal distribution; and the power of that t-test.

In addition, here are a couple of screen shots of the sort of thing that you get when you interactively run the Central Limit Theorem app. with samples of size n = 24 and n = 200, respectively:

Notice the "slide-bars" above the first graph : that's how you control the dynamics. There's also an "autorun" arrow in the top right corner of each box above. When you click on it, you get the autorun control box, and you can simulate various situations at will:

Recently I had a post on The Article of the Future. Just think what CDF is going to do for your journal articles and e-books. You can see a great example of the former on the Wolfram site, here. Why not download the CDF player, and take a look!

© 2011, David E. Giles


  1. Very interesting, I”ve been looking for this kind of applications many times before and CDF player looks very good. Please let us know if you find out about other applications like this one. Thank you!

  2. Raluca: Thanks for the comment. I'll certainly be keeping my eyes open.



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