{"blocks": [{"key": "c12ea0e1", "text": "Scenario", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "f0047c30", "text": "Newsfeed advertising team comparing two ad-insertion strategies.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "869d1c60", "text": "Question", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "8d35b9a6", "text": "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?", "type": "unordered-list-item", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "64157f35", "text": "Hints", "type": "header-two", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}, {"key": "4d4ce9d1", "text": "Use linearity of expectation and binomial probabilities; P(≥1) = 1 – (1–p)^n.", "type": "unstyled", "depth": 0, "inlineStyleRanges": [], "entityRanges": [], "data": {}}], "entityMap": {}}