PRACTICE GUIDE VALKYRIE
Valkyrie Probability & Estimation Practice Test
This guide offers probability & estimation preparation for readers interested in Valkyrie Trading. The general practice ranges below are not a verified assessment specification for that employer.
Those are ranges across firms running this format rather than Valkyrie 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.
These are Outcry preparation topics, not a verified current firm assessment specification. Check your role-specific invitation for the test, timing, tools and recruitment stage.
Outcry is not affiliated with Valkyrie 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 Valkyrie Trading’s own.
What it screens
A trading firm with public opportunities in trading and technology.
- ✓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 Valkyrie Trading
A trading firm with public opportunities in trading and technology. The topics here are Outcry preparation suggestions, not a verified firm syllabus or recruiting stage.
Outcry also has 4 other topic guides for readers interested in Valkyrie Trading. Their presence does not mean applicants must sit that many tests or that they belong to one recruiting round.
The format
These are general practice ranges, not a verified current assessment specification for Valkyrie Trading. Check the employer’s invitation for the actual format.
| 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 | Preparation topics · employer round unconfirmed |
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 Valkyrie Trading’s.
Expected value and odds
Pricing a bet, converting between odds and probabilities, and deciding whether to take it.
Example
You win 20 with probability 65% and lose 20 otherwise. Expected value per bet?
- 6
- 13
- 20
- 0
Answer 6
65% × 20 − 35% × 20 = 6. The edge is the probability gap times the stake.
Counting and combinatorics
Arrangements, selections and the complement trick that turns a hard count into an easy one.
Example
A 4-sided die is rolled until it shows a 4. The first 4 on roll n pays $4^n. The game is stopped after 9 rolls and pays nothing if no 4 has come up. What is the expected payout?
Answer 9841
The first 4 lands on roll n with probability (3/4)^(n-1) x 1/4, and that roll pays $1 x 4^n. Multiplying gives $1 x 3^(n-1), so the terms grow rather than shrink and the sum over the 9 rolls is $9841. Same shape as St Petersburg: the payout outruns the probability, so only the cap keeps the expectation finite.
Distributions you should know cold
Binomial, geometric and uniform means and variances, applied rather than quoted.
Example
A walker takes 6 steps, each equally likely left or right. What is the chance of ending exactly where it started?
- 62.5%
- 31.25%
- 50%
- 12.5%
- 16.67%
Answer 31.25%
It needs exactly 3 of each direction: C(6,3) = 20 out of 2^6 = 64, which is 31.25%.
Estimation under uncertainty
A number nobody knows exactly, reasoned to the right order of magnitude out loud.
Example
4 crates arrive at a receiving dock holding spacers, shims, gaskets and bolts, 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.
Symmetry arguments
Questions that collapse to one line once you notice the two cases are mirror images.
Example
How many ways can 4 items be chosen from 11 when order does not matter?
Answer 330
C(11,4) = 330. The ordered count would be 4! = 24 times larger.
Reading the question exactly
At least, exactly, and given that - the three phrases that change the answer entirely.
Example
A sum of 18,000 is lent for two years at 9% a year. How much more does compound interest earn than simple interest?
- 145.8
- 1,620
- 3,240
- 291.6
Answer 145.8
Over two years the gap is the interest earned on the first year's interest: P x (r/100)^2 = 18,000 x 0.09^2 = 145.8. The principal and the first year's interest are identical under both schemes.
What a good score looks like
No current employer cutoff is verified for these general practice ranges. Use the worked examples to identify what to study and check your role-specific invitation for the actual assessment rules.
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.
- 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 Valkyrie Trading
Common questions
- Is the Valkyrie probability & estimation test multiple choice?
- This guide uses multiple choice or a typed number for practice. The employer’s current answer format was not verified here.
- How long is the Valkyrie probability & estimation test?
- This guide uses general practice ranges of 10 to 20 questions in 15 to 45 minutes. They are not a verified current employer format.
- Is there negative marking on the Valkyrie 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?
- The warm-up drills are free with no account, and every pass opens the rest of the drills linked on this page. Questions are generated fresh each run, so there is nothing to memorise between attempts.