Context
You are interviewing for a data scientist role on an ads team. You are asked to demonstrate knowledge of common probability models for clicks, basic expectations, and asymptotic behavior.
Tasks
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Name three probability distributions suitable for modeling ad clicks and state the core assumption of each.
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For those distributions, write their expectation and variance formulas.
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If 90% of users are high-intent and 10% are low-intent, each with an expected click-through rate (CTR) of 0.30, compute the overall expected CTR.
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Sketch (describe) the PDF of an exponential distribution and explain what happens to its shape as sample size becomes very large (hint: think about the sampling distribution/CLT).