Module 07 Knowledge Check
5 questions. Pass mark 4 out of 5. Answer every question before checking the answer key below, then retry after reading the feedback.
1. The effect size that usually needs least explaining is…
- A. Cohen's d
- B. the raw difference in the reader's own units
- C. the odds ratio
- D. the p-value
2. Cohen's d can differ between two studies with the same raw difference because…
- A. the sample sizes differ
- B. it divides by the spread, which differs
- C. it uses the median
- D. the alpha levels differ
3. Risk ratios and odds ratios agree closely only when…
- A. the sample is large
- B. the outcome is rare
- C. the groups are equal-sized
- D. the data is normal
4. Two studies both reject the null; the smaller one's interval is five times wider. This means…
- A. the smaller study found a larger effect
- B. only the larger study tells you the effect size
- C. the smaller study is invalid
- D. the results conflict
5. A 0.348-point difference, p = 0.0002, with the whole interval below a pre-set 2-point bar is…
- A. a success
- B. evidence that a meaningful effect has been ruled out
- C. inconclusive
- D. a reason to collect more data
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Answer Key and Explanations
Check these only after attempting every question.
1. B — the raw difference in the reader's own units
'15.1 ms faster, interval 4.5 to 25.7' requires no conventions and no translation.
2. B — it divides by the spread, which differs
In the lesson d moved from 0.28 to 0.74 largely because the population was less variable.
3. B — the outcome is rare
With a common outcome the lesson's risk ratio of 1.5 came with an odds ratio of 2.25.
4. B — only the larger study tells you the effect size
The small study's interval spanned trivial to large. It established existence and nothing else.
5. B — evidence that a meaningful effect has been ruled out
The data does not demonstrate a worthwhile effect; it excludes one.
Practical Check
Apply this module to your own work: complete the module activity for *Effect Sizes and Practical Significance*, then write one sentence naming what your result shows and one naming what it does not.
Strong Answer Pattern
A strong answer names the task, the evidence used, the check performed, and the remaining limitation. It avoids "proved", "guaranteed", or "always" unless the evidence genuinely supports it.