**FAQs about Effect Size**

- What is an effect size?
- Can you give me some examples of an effect size?
- Why does my research methods textbook have no entry for “effect size”?
- How to report an effect size
- Cohen’s effect sizes
- 3 reasons for reporting effect sizes
- Why are journal editors increasingly asking authors to report effect sizes?
- Which editors encourage the reporting of effect sizes?
- Why can’t I just judge my result by looking at the
*p*value? - Why can’t I just report the
*R*^{2}? - What are the two families of effect size?
- What’s a good effect size index for comparing the means of two groups?
- Where can I find a good effect size calculator?
- How to interpret an effect size
- Can you recommend a plain English introduction to effect sizes?

**FAQs about Statistical Power**

- What is statistical power?
- How to calculate statistical power?
- How to increase statistical power?
- What is an ideal level of statistical power?
- What do alpha and beta refer to in statistics?
- What’s the difference between Type I and II errors?
- How big a sample size do I need to test my hypotheses?
- How do I know if my study has enough statistical power?
- What’s wrong with post hoc power analyses?
- Can you recommend a good power calculator?
- Can you recommend a plain English introduction to power analysis?

**FAQs about Interpreting Research Results**

- What is the difference between statistical and substantive significance?
- How do researchers confuse statistical with substantive significance?
- Can a result be statistically nonsignificant but important?
- Why should I interpret the substantive significance of my results?
- Which journal editors insist researchers interpret the substantive significance of their results?
- What does a statistical significance test actually tell us?
- What does a
*p*value represent? - Why is it a dumb idea to interpret results by looking at
*p*values? - Why do you say a
*p*value is a confounded index? - What are some conventions for interpreting different effect sizes?
- When are small effects important?
- What is the “curse of multiplicity”?

**FAQs about Meta-Analysis**