Probability Interview Review Sheet
A probability interview review sheet covering coins, dice, cards, urns, Bayes, random walks, counting, distributions, and final checks.
Candidates consolidating probability-family prep before quant interviews.
Coins and repeated trials
Review fixed flips, biased coins, streaks, geometric waiting times, and pattern states. Check whether the prompt is fixed-length, first-success, or overlapping-pattern waiting.
Dice and finite spaces
Review ordered outcomes, sums, maxima, expected values, and rerolls. Remember that sums are not uniform and that maxima are often easier with cumulative counts.
Cards, urns, and sampling
Review replacement, order, combinations, hypergeometric counts, and conditioning after revealed information. Most errors come from stale denominators or mixed sample spaces.
Bayes and conditioning
Review priors, likelihoods, posteriors, tree diagrams, and base rates. Convert percentages to counts when the posterior feels unintuitive.
Random walks and states
Review hitting probabilities, expected time, absorbing boundaries, Markov-style states, and the difference between probability and expected-time recurrences.
Final checks
Before an interview, practice explaining sample space, method choice, and sanity checks aloud. A review sheet is only useful if it leads to cleaner live reasoning.
Practice the pattern
Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.