REVIEW: The design of a simple two groups experiment

About Graham R Gibbs

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

The PsychFiles Episode 45: Basic Research Design – Part 1

By Dr. Michael Britt

Reviewed by Graham R Gibbs

This is one of over 90 videos mainly on psychology and related issues. Some, such as this video, cover aspects of research methods. In this Dr. Michael Britt, who is the author of all the Psych Files videos and who works full time for Pearson Education and serves as an adjunct instructor with Marist College, Poughkeepsie, New York USA, examines a simple two groups experimental design. To keep it amusing he uses an example from a website called HairMixer in which the user can create images combining their face with a variety of hairstyles and Britt uses these to design a simple experiment to test the effect of hair type on perceptions of a person’s credibility. The video covers, in an instructive and easily understood way, an introduction to ideas of independent and dependent variables, t-tests, ANOVA, experimental design, between subjects, within subjects variation and confounding factors.

This video is about 15 minutes long and contains animated images and a voice over and was posted on February 6th, 2008. Video quality and sound quality are very good and the image can be played at full screen size.

It is suitable for undergraduate students taking a course on experimental design and could be used as supplemental material for sessions or, as it is quite short, could be used in class as an illustration followed by e.g. a question and answer session, a short knowledge checking quiz or discussion of further design variations. Although statistics are mentioned in the video, there is no explanation of their meaning or their use. Students would need separate instruction in this. The video probably needs to be embedded in deeper explanations of key concepts like, experimental manipulation, independent and dependent variables, controls and groups in experiments and statistical tests. It could be used at an introductory level for postgraduate students. Although the example is psychological, it is easily understood and could be used in any discipline teaching experimental design.

The video is on a commercial website, but there seem to be no restrictions on the playing of the videos. However, there is no Creative Commons (CC) license and there is no information about any reuse of the materials other than simply playing the video.

It can be found on the Psych Files website:


And on iTunes University.

Related materials

Also from PychFile

  • Episode 109: Correlation and Causation: November 10th, 2009  <>
  • Episode 102: How to Create an Online Experiment on Eyewitness Testimony Accuracy: August 24th, 2009 <>
  • Episode 52 (video): Research Design Part 2 – Factorial Designs: March 31st, 2008 <>


Gibbs, Graham R (2011) ‘The design of a simple two groups experiment’. Review of Britt, Michael (2008) The PsychFiles Episode 45: Basic Research Design – Part 1, Methods Website <>

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