4-Week Quant Interview Study Plan
A four-week quant interview study plan for probability, expected value, market making, mental math, mocks, and targeted review.
Candidates with about one month before quant interviews who need a focused schedule.
Week 1: diagnose and rebuild foundations
Week one is diagnosis plus denominator discipline. Open with a mixed set of twelve to fifteen questions and score sample-space setup, counting, conditioning, expected value, mental arithmetic, and explanation quality as separate lines - a single percentage tells you nothing about what to fix. Spend the remaining four sessions on the two lines that scored worst, which for most candidates are sample-space setup and conditioning: ordered versus unordered, with versus without replacement, and what the denominator becomes once information is revealed. Close the week by retaking the questions you missed, cold.
Week 2: probability and expected value
Week two covers the material that recurs across nearly every quant interview: coins and stopping rules, dice and counting, cards without replacement, Bayes tables, combinatorics, and linearity of expectation. Two anchors are worth over-learning. The geometric waiting time: a fair coin needs E = 1 + (1/2)E = 2 flips to the first head, and a coin with head probability p needs 1/p. And linearity: the expected sum of three fair dice is 3 x 3.5 = 10.5, with no enumeration of 216 outcomes, and it holds even when the dice are dependent. Keep a one-line error log where each miss produces a rule such as "I treated unordered hands as ordered" or "I forgot to condition on the first step."
Week 3: games, estimation, and speed
Week three converts math into decisions: market making games, betting prompts, Fermi estimation, and arithmetic under light time pressure. The scoring changes here, because a defensible wide market beats a precise tight one. If you estimate a jar holds 800 coins and your honest uncertainty is around plus or minus 20 percent, quoting 650 at 950 is right and quoting 790 at 810 is not - the tight market is an invitation to be picked off by whoever knows more than you do. Review each game on fair value, width, inventory, and update quality rather than on whether it made money.
Week 4: mocks and targeted repair
Week four is two or three mocks plus repair, and nothing new. Introducing a fresh topic in the final week reliably costs more than it returns. After each mock, name the single failure mode that cost the most and fix that before the next one: if every mock breaks on conditional probability, the next day is Bayes tables, not options vocabulary. Retest the repair inside a mixed set, because a method only counts as fixed when it survives without being announced in advance.
Concrete schedule example
A working candidate might run five 60-minute sessions a week: three focused problem blocks, one timed mixed set, one market making or estimation block, plus a 20-minute review. A student with more time can split the same load into six shorter daily sessions plus one longer weekend mock. Either way, the ratio that matters is roughly three parts practice to one part review. Most candidates run closer to ten to one, then wonder why the same errors keep returning.
Common mistakes
A four-week plan fails when week four looks identical to week one. If your error log changes and your schedule does not, you are practicing rather than preparing. The other reliable failures are spending the month collecting resources, redoing problems you have already solved because they feel good, and taking mocks without reviewing them - an unreviewed mock is an expensive way to confirm that you get nervous.
Practice the pattern
Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.