JentooPsychology

AP® Psychology · Science Practices: Research Methods and Data

3.C Effect Size and Statistical Significance

Watch it drawn4 questionsPractice

Watch it explained

  1. How it worksHow does effect size measure the gap between two distributions rather than the chance of a fluke?
  2. Worked exampleDraw two group distributions for effect sizes of 0.2, 0.5, and 0.9.
  3. Common mistakeWhy isn't a statistically significant result automatically an important one?
  4. Going furtherWhat happens to statistical significance when the same effect is tested on 10000 people?

Check yourself

Your turn1 of 2
Two groups are compared on a task: the treatment group scores an average of 84, and the control group scores an average of 64. If the pooled standard deviation for both groups is 14, what is Cohen's d effect size for this comparison?

End of topic.

Next: 2.D Research Ethics →