Quant interview prep guides

Sampling Before Betting Interview Questions

Sampling before betting interview questions for deciding whether observation or exploration improves expected value enough to justify its cost.

Candidates facing sample-then-act, observe-then-bet, and exploration prompts.

Sampling is a decision before the decision

A sampling prompt asks whether it is worth paying time, money, or opportunity cost to learn more before choosing a bet or action.

Start with the prior decision

Compute what you would do without sampling. This baseline tells you how much improvement the sample must create.

Model sample accuracy

A sample is useful only through how it changes your probability estimate. State whether the sample is noisy, biased, independent, or costly.

Concrete example

If sampling costs 0.50 and only improves expected payoff by 0.30, sampling is negative value even if it gives more information.

Connect to stopping

Some prompts let you sample repeatedly. Then the key question becomes whether the next sample has positive marginal value.

Common mistakes

Candidates often assume more information is automatically better. In expected value terms, the information must change action enough to pay for itself.

Practice the pattern

Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.