"Why I need a new race bike"
A student who races bicycles wants to persuade his parents to buy him a new bike. Low technical audience, high personal stakes.
- Vague question
- "Shouldn't I get a better bike?"
- Refined question
- "Will a bike 1.5 kg lighter cut my 8 km club-climb time enough to move me into the top 5 of my age group this season?" It's specific, it interests the audience, and the reasoning is plausible (less weight means less energy uphill).
- Audience
- His parents. They care about cost, commitment and safety. They read simple charts, so show one idea per chart, with no raw 180-day logs.
- Descriptive Q
- "How many hours did I train per week over the last six months?"
- Exploratory Q
- "Do club riders who train more finish faster? Where does my gap come from: fitness or the climbs?"
- Answerability
- He has no data on himself riding the new bike yet. Use direct data where he can, such as a test ride on the same climb, and be honest when he relies on indirect data like manufacturer claims (slide 22).
- Alternatives
- A new bike, new wheels only (cheaper, gets most of the weight saving), a second-hand bike, or waiting a season. Give one pro and one con for each. He recommends one.
| Data point | Chart | Why this chart |
|---|---|---|
| Weekly training hours, last 26 weeks | Line chart | One variable over time shows that he trains regularly. |
| Monthly time on the club climb | Line chart with the plateau annotated | Shows progress, then the flat stretch. The annotation tells parents where to look (slide 25). |
| His race times vs. 8 competitors | Bar chart, sorted, his bar highlighted | Compares a categorical variable (the rider). It's easy to read. |
| Training hours vs. race time for club riders | Scatter plot | Two numerical variables changing together. Keep this one for himself, because it may be too technical for his parents. |
Quiz link: specificity, answerability, plausible framework, descriptive vs. exploratory questions, the audience setting the level of technical detail.