Expected Value with Variance Interview Questions
Expected value with variance interview prep for comparing payoff distributions, risk, spread, downside, and single-metric mistakes.
Candidates practicing risk-aware payoff comparisons.
EV and variance answer different questions
Expected value measures average payoff. Variance measures spread around that average.
Compare distributions
Two choices can have the same expected value and very different variance. Interviewers may want you to notice that distinction.
Concrete example
A certain payoff of 5 and a 50/50 payoff of 0 or 10 both have expected value 5, but the second has more variance.
Downside and constraints
Variance is not the whole story, but it can flag that a high-EV choice has large swings or downside.
Decision prompts
If the prompt asks for fair value, EV may be enough. If it asks what to choose, discuss variance, utility, and constraints.
Common mistakes
Candidates often pick the highest EV without mentioning that the distribution may be unacceptable under the stated constraints.
Practice the pattern
Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.