PRACTICE GUIDE ALL OPTIONS
All Options Probability & Estimation: what the test is, and how to train for it
All Options 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 All Options'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 All Options 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 All Options’s own.
What it screens
An Amsterdam equity derivatives market maker with a desk in Austin, Texas.
- ✓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 All Options
An Amsterdam equity derivatives market maker with a desk in Austin, Texas. 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 3 other screens at All Options, 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
All Options 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 All Options’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.
Counting and combinatorics
Arrangements, selections and the complement trick that turns a hard count into an easy one.
Example
A drawer holds 11 fair test coins and one with heads on both faces. One is taken out at random and tossed repeatedly, coming up heads every time. How many heads in a row are needed before the probability that it is the two-headed one first reaches 0.98?
Answer 10
Posterior after h heads is 2^h/(2^h + 11), from prior odds 1 to 11 multiplied by a likelihood ratio of 2^h. Setting that at or above 0.98 gives 2^h >= 11 x 0.98/(1 - 0.98) = 539, so h = 10. Check: 9 heads gives 0.979, which is short, and 10 heads gives 0.9894. Each head is one doubling of the odds, so the count grows only with the log of the pile.
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%
Symmetry arguments
Questions that collapse to one line once you notice the two cases are mirror images.
Example
4 crates arrive at a receiving dock holding rivets, spacers, bushings and clips, one content each. Each crate carries a label naming one of those 4 contents, no two labels the same, and every label is on the wrong crate. Opening a crate shows what is in it. How many crates must be opened, in the worst case, to relabel all 4 correctly?
Answer 2
The label-to-contents map is a permutation with no fixed point, and there are 9 of those on 4 items. Opening a crate reveals its contents and splits the live set; picking the next crate after seeing the last result, a minimax search over every opening order gives 2 as the worst case. With 4 = 3 the two possible arrangements are the two rotations, and one look separates them. The general pattern: the last two crates settle themselves only when the two contents left both clash with their own labels.
Reading the question exactly
At least, exactly, and given that - the three phrases that change the answer entirely.
Example
Revenue by division, $m Division 2020 2021 2022 2023 Commodities 165 345 305 225 Macro 230 270 290 385 Rates 240 170 325 250 Credit 320 455 380 460
Which division added the most revenue in absolute terms between 2021 and 2023?
- Commodities
- Rates
- Macro
- Credit
Answer Macro
Changes: Commodities -120, Macro +115, Rates +80, Credit +5. Macro is the largest at +115.
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.
- 02Do them timed. A probability question you can solve in four minutes and the paper gives you ninety seconds for is a question you cannot solve.
- 03Work the complement first whenever the question says at least or at most. It is usually the shorter route and it is almost always the intended one.
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 All Options
Common questions
- Is the All Options 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 All Options 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 All Options 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.