REVIEW: A visual tool for exploring ANOVA

About Graham R Gibbs

Reader in Social Research Methods at the University of Huddersfield. National Teaching Fellow.

Understanding ANOVA Visually (1998, 2000) by Tom Malloy (University Utah, USA)

Reviewed by Graham R Gibbs

This resource is a visual, manipulable tool for examining the relationship between the variance between means, the variance within groups and the resulting F value. In the tool there are four groups that are compared and the user can change the mean value of each group (by sliding it up and down) and change the variability within each group (by clicking on plus and minus buttons). After each change a moving bar shows the resulting F value. The user quickly gets a feel for how increasing the variability affects the F value and how changing the means of one or more groups affects it.

Visual ANOVA

The tool requires some knowledge of what ANOVA does and what it is used for. By using it, the learner will get a good feel for what the statistic is trying to show. So it is best suited for those who have already done some basic statistics and understand when and how to undertake an ANOVA. The tool helps improve students’ understanding of the results they get. The tool could be used as an illustration in a lecture on ANOVA, but is best used individually by students in labs or on their own computers. It uses Adobe Flash and will need the appropriate Flash plugin.

There are links to instructions for use, an online lecture on ANOVA and some homework files (with answers). However, one other link is broken.

The tool is openly available on a website, but is marked copyright, so use in its current form is acceptable, but modification needs the author’s permission.

The tool is also referenced in the Merlot archive:


Gibbs, Graham R (2011) ‘A visual tool for exploring ANOVA’. Review of Malloy, T. (2000) Understanding ANOVA Visually, Methods Website <>

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