Monday, December 15, 2014

Kristopher Magnusson's "Interpreting Cohen's d effect size"

Kristopher Magnusson (previously featured on this blog for his interactive illustration of correlation) also has a helpful illustration of effect size. While this example probably has some information that goes beyond an introductory understanding of effect size (via Cohen's d) I think this still does a great job of illustrating how effect size measures, essentially, the magnitude of the difference between groups (not how improbably those differences are). See below for a screen shot of the tool.

http://rpsychologist.com/d3/cohend/, created by Kristopher Magnusson

Wednesday, December 10, 2014

UCLA's "What statistical analysis should I use?"

This resource from UCLA is, essentially, a decision making tree for determining what kind of statistical analysis is appropriate based upon your data (see below).
Screen shot from "What statistical analysis should I use?"
Now, such decision making trees are available in many statistics text book...however...
what makes this special is the fact that with each test comes code/syntax as well as output for SAS, Stata, SPSS, and R. Which is helpful to our students (and, let's be honest, us instructors/researchers as well).