Module 5 Worksheet: Reading Charts and Distributions
Scenario
You are helping a beginner analyst review a small synthetic dataset. Your job is not to sound impressive. Your job is to make the safest useful statement.
Data
Dataset: chart-reading-summary.csv
| chart_id | chart_type | intended_message | sample_size | axis_risk | safe_observation |
|---|---|---|---|---|---|
| CH01 | bar chart | Course B has more completions than Course A | 80 | y-axis starts above zero | Course B appears higher but the axis may exaggerate the difference. |
| CH02 | line chart | Weekly signups increased after a campaign | 12 | no comparison group | Signups rose after the campaign but other causes are still possible. |
| CH03 | histogram | Most delivery times are under 45 minutes | 120 | outlier hidden by wide bins | Most times are below 45 minutes but bin width may hide long delays. |
| CH04 | scatter plot | Study hours and score move together | 60 | no confounder shown | Higher study hours are associated with higher scores in this sample. |
| CH05 | box plot | Group A has a lower median wait time | 45 | small sample per group | Group A's median appears lower but sample size should be checked. |
Your Task
Pick three chart scenarios and write one observation plus one caution for each.
Questions
- What is the statistical question?
- What is the unit of analysis?
- Which variables matter most?
- What summary, comparison, or visual check is suitable?
- What does the evidence suggest?
- What should not be claimed?
- What limitation should be mentioned?
Write Your Conclusion
Write two to four careful sentences. Use plain English. Do not use words like proves, guarantees, or always unless the evidence truly supports them.
Self-Check
- Did I name the question?
- Did I use the right denominator or comparison?
- Did I avoid claiming more than the data can support?
- Did I mention uncertainty, bias, assumptions, or limits where needed?