Optimize interval-scoring strategy
Five-Round Interval-Estimation Game: Optimal Intervals and Risk Allocation
You play five independent rounds. In round i, an unknown numeric answer A is drawn from a continuous distribution. You announce a closed interval [L, U]. The round score is:
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0 if A ∉ [L, U]
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L/U if A ∈ [L, U]
Total score is the sum across five rounds. The target is total ≥ 2.0. Assume that for each round you have a subjective continuous pdf f(a) (cdf F) for A.
Answer the following:
(a) Formulate the optimization for choosing L and U that maximizes the expected per-round score E[(L/U)·1{A ∈ [L, U]}] given a known continuous pdf.
(b) Derive the first-order optimality conditions (FOCs). Discuss how the optimal coverage probability compares to conventional confidence levels under light- vs heavy-tailed beliefs.
(c) Describe a strategy to allocate risk across five rounds (e.g., dynamic programming or heuristics) to maximize the probability of achieving total ≥ 2.0, including how to adjust interval tightness after early wins/losses.
(d) Provide a quick mental method for approximately optimal [L, U] under log-normal beliefs (A > 0), and explain how you’d adapt for heavy tails.
(e) Outline a simple simulation to validate your strategy and estimate the probability of meeting the ≥ 2.0 target.
Assume U > 0 and typically A > 0 (most market-making questions are positive). If A could be negative, you may work on a transformed scale (e.g., log of absolute value) or restrict to positive-support questions.
Constraints & Assumptions
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Preserve the scope, facts, inputs, and requested outputs from the prompt above.
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If the prompt leaves a detail unspecified, state a reasonable assumption before relying on it.
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Keep the answer interview-ready: concise enough to present, but concrete enough to implement or evaluate.
Clarifying Questions to Ask
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Clarify the random variables, distributional assumptions, independence assumptions, and desired output.
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Show enough derivation for the interviewer to follow the reasoning.
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Explain how you would validate the result with simulation or sensitivity checks.
What a Strong Answer Covers
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A correct setup with definitions, formulas, and boundary conditions.
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A step-by-step derivation or estimation plan.
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Interpretation of the result, including uncertainty and practical limitations.
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Checks for assumptions, edge cases, and numerical stability.
Follow-up Questions
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How would the result change if the assumptions were relaxed?
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Can you verify the answer with a simulation?
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What is the most likely source of estimation error?