Compare Ad-Insertion Strategies: Expected Ads and Probabilities
MetaData Scientist · Onsite
Last updated
Evaluates probability, expectation, and variance for newsfeed ad-insertion strategies. Strong answers compute expected ad load, at-least-one exposure probability, and explain why equal expected counts can still produce different user experiences.
Scenario
Newsfeed advertising team comparing two ad-insertion strategies.
Question
Strategy A: each post independently has 4% chance of being an ad. What is the expected number of ads in 100 posts? 2. Strategy B: exactly one ad is randomly inserted in every block of 25 posts. Compare expected ads per 100 posts. 3. Under Strategy A, what is the probability a user sees at least one ad in the next 25 posts?
Hints
Use linearity of expectation and binomial probabilities; P(≥
- = 1 – (1–p)^n.
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