Archive for June, 2011

Great new tutorial on Hypothesis Testing

Saturday, June 11th, 2011

J David Eisenberg has written a great new tutorial on hypothesis testing and here is a guest post from him for the SOFA blog. Enjoy:

I teach a psychology research methods course at a local community college. Every semester, I see the students’ confusion about hypothesis testing and significance levels. Even at the end of the semester, there are always a few students who think that a statistical result with a probability of .001 must *not* be significant, because the number is so small.

I do explain the concept during one lecture, but that just doesn’t do the trick. I could write a web page with the explanation, but I’m sure I’d get a TL; DR [1] from the students. So, I decided to make the explanation in the form of a visual novel [2] (VN). I used the Ren’py [3] visual novel engine to create the script, and it worked fine. The problem is, you need to download a fairly large file in order to display the VN; again, something that students would probably not be eager to do. The solution, which Grant [Developer of SOFA Statistics] suggested, was to make it all web-based. After some failed experiments with canvas and SVG, I was able to achieve the effects I wanted with HTML, CSS,and JavaScript. The result is at

Tutorial on hypothesis testing


50,000 downloads – another milestone

Monday, June 6th, 2011

SOFA Statistics had its 50,000th download today, and last month had over 4,600 downloads – a new record.

Download milestone

Box and Whisker Plots in version 1.0.6

Saturday, June 4th, 2011

Box and Whisker plots have been added.

Box and Whisker Plot button

In keeping with the SOFA ethos these have been made as attractive as possible:

Box and Whisker Plot

As with all SOFA output, the Box and Whisker Plots are themed and, like other charts, the content is dynamic and interactive. A minor feature added to this version is a warning about the need to include the “sofa_report_extras” subfolder to see charts.

The following bug fixes have been made:

  • Fixed bug preventing comma being used as decimal separator when importing data.
  • Fixed bug when making line charts with averages – shows smoothed data line and trend line appropriately. Also only enables or disables checkboxes for smoothed data line and trend line where appropriate.
  • Better handling of comtype errors.
  • Fixed bug in histogram code when no default limits supplied.