Module 03 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. On skewed money data the more robust pair of summaries is…
- A. mean and standard deviation
- B. median and IQR
- C. mode and range
- D. mean and IQR
2. A group of six topping a ranking of means should prompt you to…
- A. report it as the leader
- B. check n and the standard error
- C. drop the group
- D. switch to the median
3. Two groups with means of 49.6 and 50.9 and similar SDs…
- A. must have the same distribution
- B. may have very different shapes, including bimodality
- C. cannot be compared
- D. differ significantly by definition
4. Two 95% confidence intervals that overlap…
- A. prove there is no difference
- B. are compatible with a clearly significant difference
- C. mean the test is invalid
- D. cannot both be correct
5. An honest statistical sentence contains…
- A. the word significant
- B. the estimate, the interval, the p-value and n
- C. the p-value alone
- D. the estimate alone
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Answer Key and Explanations
Check these only after attempting every question.
1. B — median and IQR
One value in 61 moved the mean by 14 and the SD by a factor of five, while the median moved by less than one.
2. B — check n and the standard error
Its standard error was seven times North's. Without n and se the ranking reads as settled.
3. B — may have very different shapes, including bimodality
One of them was two clusters around 44 and 57, which no mean and SD can express.
4. B — are compatible with a clearly significant difference
In the lesson the intervals overlapped and the difference test gave p = 0.01 with an interval excluding zero.
5. B — the estimate, the interval, the p-value and n
'Significant' replaces four pieces of information with none of them, and carries an everyday meaning it does not have here.
Practical Check
Apply this module to your own work: complete the module activity for *Descriptive Statistics and Statistical Visualisation*, 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.