Calculate probability for user retention
Last updated: November 6, 2025
Quick Overview
Given the following scenario about revenue per session, calculate the the p-value.
Optiver
November 6, 2025148
5
4,715 solved
Given the following scenario about revenue per session, calculate the the p-value.
This analytics question from Optiver's Onsite tests your ability to think critically about data. The interviewer expects you to consider confounding variables, selection bias, and the difference between correlation and causation.
What the Interviewer Expects
- Design complex experimentation strategies for tricky scenarios
- Handle multi-armed bandits, switchback experiments, and quasi-experiments
- Address long-term effects vs short-term metrics
- Propose causal inference methods when randomization is not possible
- Build a measurement framework that connects metrics to business value
- Discuss organizational experimentation culture and maturity
Key Topics to Cover
How to Approach This
- Define success metrics carefully. A good metric is measurable, actionable, and aligned with business goals.
- Run experiments long enough to account for novelty effects and weekly seasonality.
- Use funnel analysis to identify where users drop off for maximum optimization impact.
- Segment results by key dimensions (platform, country, user cohort) to catch hidden patterns.
- Consider network effects and interference between treatment and control groups.
Possible Follow-up Questions
- What would you do if a stakeholder wants to end the experiment early because initial results look good?
- How would you handle seasonality in your experiment?
- What if you discover a bug in the logging during the experiment?
- How would you handle an experiment where the control and treatment groups are different sizes?
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Browse Analytics QuestionsSample Answer
Problem Setup
To analyze user retention for Optiver based on revenue per session, we want to determine the probability of a user returning after their first session. The analytical question is: "What is the probabi...
Methodology
For this problem, we'll use a two-sample proportion test to compare the retention rates of users who had above-average revenue in their first session against those who had below-average revenue.
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