Probability
The probability round trading assessments use, against a clock. Expected value and binomial to warm up, then Bayes, biased gambler's ruin, random walks round a circle, reroll games, coupon collecting and the other questions people get wrong most often. Five options, no going back, and skipping is the right move more often than it feels.
Leaderboard
Correct answers, less one per wrong one.
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Counts towards the overall leaderboard across all ranked games.
Too easy? Sit the real format.
Probability (Hard) runs the way candidates describe Beat the Odds: 30 questions, a strict 90 second clock on each, coarse options where you pick the closest value, no feedback until the end and nothing from the easy tiers, on its own leaderboard.
How it is scored
A correct answer scores +1, a wrong one costs 1, and a skip costs nothing, so guessing at random loses marks on average. Your score is what is left, floored at zero. That is the shape the real probability rounds are reported to use, and it is there to train the habit the format rewards: leave the question.
Where we had to choose
Accounts of the real thing disagree on the length. It is variously reported as 10 questions in 15 minutes, 30 minutes at 90 seconds each, and 30 questions at 90 seconds each. Nobody publishes the deduction rate either, only that wrong answers lose marks. This drill is a six minute sprint at 1 for a wrong answer, which is a choice we made, not a claim about anyone's test. The questions are the families candidates report from the real rounds, written so that a good estimate gets you to the right option in about twenty seconds.
The wrong options are not padding
Every distractor is the answer you reach by making one specific mistake: forgetting the binomial coefficient, drawing with replacement when the question says without, multiplying a per-trial chance by the number of trials, or reading a test's sensitivity back as the answer. If an option looks right, check which mistake makes it right.
More timed drills
Expected value with a price attached is in Dice Markets, the same arithmetic to the nearest percent is in Pot Odds, and every ranked game feeds the overall leaderboard.
These are practice formats written by simplytk. They are not real assessment questions and simplytk is not affiliated with, endorsed by or connected to any trading firm or assessment provider. All trade marks belong to their owners.