Analyze Profit Decline: Data Collection and Hypothesis Testing
Company: Roku
Role: Data Scientist
Category: Analytics & Experimentation
Difficulty: medium
Interview Round: Technical Screen
##### Scenario
You manage a coffee shop whose profits have recently declined.
##### Question
How would you systematically analyze the reasons behind the drop in profit? What data would you collect, what metrics would you calculate, and what hypotheses would you test?
##### Hints
Think funnel (traffic → conversion → ticket size), cost changes, seasonality, competitors, and external factors.
Quick Answer: Evaluates diagnostic analytics for a coffee shop profit decline. Strong answers collect transaction, cost, labor, channel, inventory, and external data, decompose profit into traffic, conversion, AOV, margin, and cost drivers, test hypotheses, and recommend targeted actions.
Statistical comparisons, regression, DiD if a change affected some stores or channels, and time-series analysis.
Part 4 - Validate and Act
How would you validate findings and propose next steps?
What This Part Should Cover Guidance
Robustness checks, triangulation, small pilots, owner interviews, and operational audits.
Action recommendations tied to the diagnosed driver.
What a Strong Answer Covers Guidance
A strong answer decomposes profit into revenue and cost drivers, gathers both internal and external data, tests concrete hypotheses, and recommends actions based on measured contribution.
Follow-up Questions Guidance
What if revenue is flat but profit falls?
How would you distinguish lower foot traffic from lower conversion?
What would you test first if labor cost increased sharply?