PRACTICE GUIDE JUMP TRADING
Jump Trading Probability & Estimation Practice Test
Jump Trading does not publish the shape of its probability & estimation screen, and candidates describe it as 10 to 20 questions in 15 to 45 minutes, roughly one to three minutes per question, answered by picking one of the options.
Those are ranges across firms running this format rather than Jump Trading's own figures, so treat them as the shape to train against and check the instruction screen on the day for the marking rule.
Outcry is not affiliated with Jump Trading and has no access to their assessment content. This guide describes an assessment format that candidates report publicly; the questions here are generated by Outcry and are not Jump Trading’s own.
What it screens
A quantitative trading firm known for low-latency infrastructure and research across futures, equities and crypto.
- ✓Expected value computed fast and used to make a decision
- ✓Conditional probability and Bayes updates without formal notation
- ✓Ranking likelihoods rather than computing them exactly
- ✓Fermi estimation: decomposing an impossible question into three easy ones
Where it sits at Jump Trading
A quantitative trading firm known for low-latency infrastructure and research across futures, equities and crypto. What that means for the screen is that the questions tend to be drawn from the work rather than from a textbook, so the format below is the shape to train against rather than a syllabus.
Candidates also report 2 other screens at Jump Trading, covered separately on this site. Where a firm runs several, they usually sit in one round rather than spread across the process, so the pacing of the whole set matters more than any single section.
The format
Jump Trading does not publish this screen's shape, and it varies between firms, so these are the ranges candidates report rather than exact figures.
| Questions | 10 to 20 |
|---|---|
| Time | 15 to 45 minutes |
| Per question | one to three minutes |
| Negative marking | Varies by firm and year |
| Answer style | Multiple choice or a typed number |
| Where it sits | First round, or a second technical screen |
What it tests, with a worked example
Every example below is generated by Outcry, drawn from the same question generators the timed drills run. None of them is Jump Trading’s.
Expected value and odds
Pricing a bet, converting between odds and probabilities, and deciding whether to take it.
Example
A ticket costs 5. It pays 20 with probability 50%, else nothing. Expected profit?
- 4.5
- 15
- 10
- 5
Answer 5
50% × 20 = 10; minus the 5 cost gives 5.
Conditional probability
Bayes' rule in disguise: a test result, a signal, a drawn card, and what it implies.
Example
A token starts at position 1 on the integers 0 to 4. Each step it moves left or right with probability 1/2, and positions 0 and 4 absorb. What is the expected number of steps until absorption?
- 3
- 5
- 4
- 6
Answer 3
E[steps] from i is i(N−i) - the martingale Sₙ²−n stopped at the boundary: 1·3 = 3.
Distributions you should know cold
Binomial, geometric and uniform means and variances, applied rather than quoted.
Example
1% of a population carries a trait. A screen flags 95% of carriers and wrongly flags 2% of non-carriers. Someone is flagged. What is the chance they carry it?
- 95%
- 98%
- 1%
- 32.4%
- 67.6%
Answer 32.4%
True flags are 1 × 0.95 = 0.95% of everyone, false flags 99 × 0.02 = 1.98%. The share that is real is 0.95/(0.95 + 1.98) = 32.4%.
Ranking outcomes
Ordering several events by likelihood, where only the exact order scores.
Example
A. exactly two tails in four coin flips B. two dice summing to 6 C. a queen from a full deck
Rank most likely to least likely:
- C > A > B
- A > B > C
- B > C > A
- A > C > B
Answer A > B > C
A: 37.5% · B: 13.9% · C: 7.7%
Waiting times and repeated trials
How long until the first success, and why the answer is rarely the average you expected.
Example
A fair coin is flipped 40,000 times. Give the number of heads at the TOP of the central 95% range. Nearest integer.
Answer 20196
The count has mean 20,000 and standard deviation √40,000/2 = 100. Two of those above the mean: 20,000 + 2 × 100 = 20,200.
Symmetry arguments
Questions that collapse to one line once you notice the two cases are mirror images.
Example
An index of 500 names is replicated with the largest 80, leaving 420 names worth 3.6% of the index unheld. Those 420 are equally weighted within that 3.6%, each carries 40% of idiosyncratic volatility, and their idiosyncratic moves are independent. What is the annual tracking error of the basket?
- 1.440%
- 40.000%
- 0.070%
- 0.003%
- 3.600%
Answer 0.070%
The systematic part of the missing names is already carried by the 80 held, so what is left is 420 independent idiosyncratic bets. Each missing name has weight 3.6%/420 = 0.0086%, so on its own it contributes 0.0086% x 40% = 0.0034% of volatility. Independent risks add in quadrature, not in a straight line, so 420 of them come to sqrt(420) x 0.0034% = 20.494 x 0.0034% = 0.070%. Adding the risks straight rather than in quadrature gives 1.440%, which is what you would get if all 420 missing names moved together, and it is sqrt(420) = 20.494 times too large. The residual is small precisely because the omitted names are many, small and unrelated, which is the whole case for partial replication.
What a good score looks like
Probability rounds are usually marked as part of a wider battery, so a standalone threshold is rarely reported. Where candidates do describe one it clusters around getting two thirds of the items right, with the caveat that these sections are short enough that two mistakes move you a long way.
How to train for it
- 01Work the standard results until they are recall, not derivation: complement, conditional, binomial mean and variance, geometric expectation.
- 02Practise setting up before calculating. Most wrong answers on these are a correct calculation of the wrong quantity.
- 03Sanity-check the magnitude before committing. A probability above one or an expectation outside the range of outcomes is a caught error, and these papers plant both as options.
TRAIN IT HERE
The drills that match each section
Likelihood Ranking
Order events from most to least likely - the exact screen-question format.
Fermi Estimation
Piano tuners in Chicago, atoms in a body - scored on order of magnitude.
Quitters Never Lose
A casino stopping-strategy game that is secretly a martingale lesson.
Tail Risk
Rare events and fat tails, and what they do to a plain expected-value estimate.
SIT THE FULL BATTERY
All the sections back to back on one clock, marked the way the real screen marks them, with a by-skill breakdown at the end. Included with any pass.
Also reported at Jump Trading
Common questions
- Is the Jump Trading probability & estimation test multiple choice?
- Reported as multiple choice or a typed number. Formats move, so treat this as the shape rather than a guarantee.
- How long is the Jump Trading probability & estimation test?
- Candidates report 10 to 20 questions in 15 to 45 minutes, roughly one to three minutes per question.
- Is there negative marking on the Jump Trading probability & estimation test?
- It varies by firm and by year. Where a paper does mark negatively, skipping beats guessing; where it does not, answer everything. Check the instruction screen before you start - it is always stated there.
- How do I practise for it free?
- Every drill linked on this page is free to play, with no account, inside a daily run cap. Questions are generated fresh each run, so there is nothing to memorise between attempts.
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