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Short diagnostic hints for the two Practice on your own problems in this chapter. Attempt each problem before opening the hint. Complete answers appear in Appendix G of The Defensible Decision: Practice Workbook.
Problem 1 — the churn-attribution chart
Restated: A support team asks Copilot to «show why churn increased in Q3.» Copilot returns a bubble chart with three variables mapped to x, y, and bubble size. Name the family Copilot picked, the family the question actually calls for, and the one-sentence direction that would steer to the right family.
Show a diagnostic hint
Diagnostic cue. Begin with the analytical question, then choose the chart family that makes its comparison visible.
Complete answers appear in Appendix G of The Defensible Decision: Practice Workbook.
Problem 2 — the promo-lift chart
Restated: A marketing analyst wants to show the Q3 promotion lifted revenue for three product lines but hurt margin on two. Copilot returns a clustered column chart. Name the two candidate families for this argument, pick the primary, and explain in one paragraph why the other family is a secondary chart, not a shared one.
Show a diagnostic hint
Diagnostic cue. Separate the relationship claim from the comparison decision before choosing a chart family.
Complete answers appear in Appendix G of The Defensible Decision: Practice Workbook.
Related on this site
- Chapter 4 companion page — further reading, self-check quiz, and the chart-family selection activity.
- Chart gallery — browse chart families with worked examples per family.
- All chapter companion pages.
- Feedback — share corrections and improvement opportunities across all chapters.
About the three-tier Practice format
Each chapter of the book closes with a three-tier Practice block adapted from Cole Nussbaumer Knaflic's course-adoption pattern in Storytelling with Data: Let's Practice!: Practice with us (one worked problem with full solution in the book), Practice on your own (open problems with complete answers in Appendix G of the Practice Workbook; this page offers short diagnostic hints), and Practice at work (an open-ended prompt to apply the chapter's move to a live artifact). This page hosts the middle tier.