Estimation question
If you were launching a bike sharing app in NYC, how many people would be interested in it?
- Estimation
- Medium
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What this question tests
Market sizing estimation: can you build a demand estimate from population, target segment, and realistic adoption assumptions.
How to approach it
- Start with NYC population, assume roughly 8.5 million residents.
- Filter to the relevant segment, assume adults who could plausibly bike for transport, roughly 60 percent, about 5 million.
- Apply an interest rate for a new bike share option, assume 10 percent would consider trying it given existing biking infrastructure and competition from Citi Bike.
- That gives roughly 500,000 interested people, then apply a realistic early adoption rate, assume 20 percent actually sign up in year one, about 100,000 users.
- Sanity check against known bike share adoption elsewhere, and adjust if this feels too high or low.
- State the final range as an estimate, not a precise figure, and name the biggest assumption driving it.
What a strong answer includes
- Builds the estimate in clear layered steps, population, relevant segment, interest, then adoption, rather than one guess.
- Accounts for existing competition, like Citi Bike, which realistically caps a new entrant's adoption.
- States which assumption most affects the final number, showing awareness of estimate sensitivity.
Common mistakes
- Using the entire city population as the potential user base with no filtering.
- Ignoring that NYC already has an established bike share service.
Likely follow-up questions
- How would this estimate change in a city with no existing bike share?
- What would most increase your confidence in this number?
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Learn the skill behind it
Chapters of the AI PM course that teach what this question tests.
- Chapter 2: Data fluency: SQL, logs, and reading the truth yourself
- Chapter 9: Prove it paid off: outcomes, economics, and pricing
- Chapter 14: Get the job: the AI PM interview loop