Module 06 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. Two groups with the same mean…
- A. have the same distribution
- B. may have nothing else in common
- C. differ only in sample size
- D. are statistically identical
2. Histogram bin width is…
- A. a display setting
- B. a modelling choice that changes the conclusion
- C. fixed by the data
- D. irrelevant above 20 bins
3. Box plots cannot show…
- A. the median
- B. the shape of the distribution
- C. the quartiles
- D. outliers
4. An error bar on a bar chart usually shows…
- A. the spread of the data
- B. the uncertainty of the mean
- C. the range
- D. the sample size
5. A category with five observations should be shown with…
- A. the same weight as the others
- B. its sample size or interval visible
- C. no chart at all
- D. a larger bar
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Answer Key and Explanations
Check these only after attempting every question.
1. B - may have nothing else in common
One may be uniform, one bimodal, one dominated by an outlier - and a bar chart shows identical bars.
2. B - a modelling choice that changes the conclusion
At three bins a clearly bimodal distribution appears as a single hump.
3. B - the shape of the distribution
Two very different distributions can share nearly identical five-number summaries.
4. B - the uncertainty of the mean
They differ by a factor of the square root of n, and readers routinely confuse them.
5. B - its sample size or interval visible
The smallest category is often the most interesting and the least stable.
Practical Check
Apply this module to your own work: complete the module activity for *Distribution Charts and Uncertainty Communication*, 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.