Random Variables Interview Questions for Quant Researchers
Quant Researchers get asked random variables differently from other quant roles - the emphasis shifts with what the job actually does. This is that slice.
127 questions, 89 of them free to practise right now. The split is 28 easy, 69 medium, 30 hard.
- A two-sigma tail probabilityEasyRandom VariablesStatisticsView →
- Average distance on an intervalEasyRandom VariablesView →
- Backing out the correlation from portfolio riskEasyRandom VariablesStatisticsView →
- Beating a product of uniformsEasyProbabilityRandom VariablesView →
- Beating three othersEasyProbabilityRandom VariablesView →
- Color switches in a drawEasyRandom VariablesExpected ValueView →
- Correlation from a summed varianceEasyRandom VariablesStatisticsView →
- Correlation under rescalingEasyRandom VariablesStatisticsView →
- Covariance of a chi-square and a ratioEasyRandom VariablesStatisticsView →
- Exactly one clears two-thirdsEasyProbabilityRandom VariablesView →
- Expected distance of a dart from centerEasyProbabilityRandom VariablesView →
- Interquartile range of an exponentialEasyRandom VariablesStatisticsView →
- Largest possible covarianceEasyRandom VariablesStatisticsView →
- Matching a uniform and an exponentialEasyRandom VariablesStatisticsView →
- Maximum of four uniforms in a bandEasyProbabilityRandom VariablesView →
- No heads in a random number of flipsEasyProbabilityRandom VariablesView →
- Normalizing a tilted densityEasyRandom VariablesCalculusView →
- Pooling two independent estimatesEasyRandom VariablesStatisticsView →
- Regressing with zero covarianceEasyRandom VariablesStatisticsView →
- Second moment from varianceEasyRandom VariablesStatisticsView →
- Six heads from a random biased coinEasyConditional Probability & ExpectationRandom VariablesView →
- Skewness of a Laplace variableEasyRandom VariablesStatisticsView →
- Spread of a two-card sumEasyRandom VariablesStatisticsView →
- Standard deviation of a correlated sumEasyRandom VariablesStatisticsView →
- Variance of an asymmetric random walkEasyRandom VariablesStochastic ProcessesView →
- Where the maximum landsEasyRandom VariablesStatisticsView →
- Whether either bus comes soonEasyProbabilityRandom VariablesView →
- A difference of three normalsMediumRandom VariablesStatisticsView →
- A low medianMediumProbabilityRandom VariablesView →
- A ratio of gamma valuesMediumRandom VariablesView →
- All six faces (coupon collector)MediumRandom VariablesExpected ValueView →
- Best linear blend of two estimatesMediumRandom VariablesStatisticsView →
- Conditional mean on a circleMediumConditional Probability & ExpectationRandom VariablesView →
- Covariance from a triangular densityMediumRandom VariablesStatisticsView →
- Covariance of sum and differenceMediumRandom VariablesStatisticsView →
- Density of a sum of two uniformsMediumProbabilityRandom VariablesView →
- Density of a uniform squaredMediumRandom VariablesCalculusView →
- Expectation as a sum of tailsMediumRandom VariablesExpected ValueView →
- Expected flips for HHMediumRandom VariablesExpected ValueView →
- Expected gap between two normalsMediumRandom VariablesView →
- Expected maximum of two diceMediumRandom VariablesExpected ValueView →
- Expected square of a random unit complex numberMediumProbabilityRandom VariablesView →
- First head strictly soonerMediumProbabilityRandom VariablesView →
- Four fives before the first sixMediumProbabilityRandom VariablesView →
- Four times as long to the first headMediumProbabilityRandom VariablesView →
- Matching floors of a logarithmMediumProbabilityRandom VariablesView →
- Maximum variance on an intervalMediumRandom VariablesStatisticsView →
- Mean over variance of a nested uniformMediumProbabilityRandom VariablesView →
- Minimum of two exponentialsMediumProbabilityRandom VariablesView →
- Order statistics of two uniformsMediumRandom VariablesStatisticsView →
- Product of two uniforms above a halfMediumProbabilityRandom VariablesView →
- Ratio of partial sumsMediumRandom VariablesExpected ValueView →
- Sampling an exponential from a uniformMediumRandom VariablesProgramming & DSAView →
- Sum and difference of perfectly correlated variablesMediumRandom VariablesStatisticsView →
- Sum of independent PoissonsMediumProbabilityRandom VariablesView →
- Sum versus twice the differenceMediumProbabilityRandom VariablesView →
- The last lightbulb to burn outMediumRandom VariablesExpected ValueView →
- Uncorrelated but dependentMediumRandom VariablesStatisticsView →
- Variance of a coin-gated payoffMediumRandom VariablesStatisticsView →
- Variance of the larger of two diceMediumRandom VariablesStatisticsView →
- Variance of the longer pieceMediumProbabilityRandom VariablesView →
- Waiting to see both facesMediumRandom VariablesStatisticsView →
- X positive given the sum is positiveMediumProbabilityRandom VariablesView →
- A half-plane, given positiveHardProbabilityRandom VariablesView →
- A small sub-triangleHardProbabilityRandom VariablesView →
- A three-way race to the first headHardProbabilityRandom VariablesView →
- Counting fives before a four and a sixHardProbabilityRandom VariablesView →
- Covariance of X with Y squaredHardRandom VariablesStatisticsView →
- Covariance with a lognormal childHardConditional Probability & ExpectationRandom VariablesView →
- Draws to beat a hidden uniformHardRandom VariablesExpected ValueView →
- Draws to pass a log thresholdHardProbabilityRandom VariablesView →
- Draws to pass twoHardProbabilityRandom VariablesView →
- HTH before HHTHardProbabilityRandom VariablesView →
- Overshoot past oneHardProbabilityRandom VariablesView →
- Penalty kicks with a shifting rateHardProbabilityRandom VariablesView →
- Range beats the midpointHardProbabilityRandom VariablesView →
- Shortest of three piecesHardProbabilityRandom VariablesView →
- Six pieces, none past a halfHardProbabilityRandom VariablesView →
- Smallest possible MGF valueHardRandom VariablesStatisticsView →
- Spread of a lognormal raised to the fourthHardRandom VariablesStatisticsView →
- Spread of a multinomial count gapHardRandom VariablesStatisticsView →
- The decreasing run of uniformsHardRandom VariablesExpected ValueView →
- Three first-heads in non-decreasing orderHardProbabilityRandom VariablesView →
- Two random segments overlappingHardProbabilityRandom VariablesView →
- Uniforms summing past 1HardRandom VariablesExpected ValueView →
- Variance of the exponential of a gammaHardRandom VariablesStatisticsView →
- Variance under random parametersHardRandom VariablesStatisticsView →
- When a uniform ratio rounds to a squareHardProbabilityRandom VariablesView →
- When the extremes sum above oneHardProbabilityRandom VariablesView →
- Two searches, neither hitsEasyRandom Variables Premium
- A convexity gap by JensenMediumRandom VariablesExpected Value Premium
- A divergent reciprocal expectationMediumRandom VariablesCalculus Premium
- At least two sixes in five rollsMediumProbabilityRandom Variables Premium
- Backing out a correlationMediumRandom VariablesStatistics Premium
- Correlation of overlapping sumsMediumRandom VariablesStatistics Premium
- Expectation of e raised to a normalMediumRandom VariablesExpected Value Premium
- Expectation of −2 ln UMediumRandom VariablesCalculus Premium
- Expected maximum of three diceMediumRandom VariablesExpected Value Premium
- Expected minimum of two diceMediumRandom VariablesExpected Value Premium
- Fourth moment of a shifted normalMediumProbabilityRandom Variables Premium
- How many trials to poll a proportionMediumRandom VariablesStatistics Premium
- Median of a linear densityMediumRandom VariablesCalculus Premium
- Memoryless waitingMediumConditional Probability & ExpectationRandom Variables Premium
- Neither die exceeds fourMediumProbabilityRandom Variables Premium
- Optimally pooling two estimatorsMediumRandom VariablesStatistics Premium
- Poisson thinning: exactly two large ordersMediumRandom Variables Premium
- Rare-event Poisson approximationMediumProbabilityRandom Variables Premium
- Remaining life of a memoryless partMediumRandom Variables Premium
- Second moment via the MGFMediumRandom VariablesCalculus Premium
- Sum of squared standard normalsMediumRandom VariablesStatistics Premium
- The first component to failMediumRandom Variables Premium
- The larger die shows a 4MediumProbabilityRandom Variables Premium
- The probability integral transformMediumRandom VariablesStatistics Premium
- Two uniforms summing below a halfMediumProbabilityRandom Variables Premium
- Variance of a compound daily totalMediumRandom Variables Premium
- Variance of a lognormalMediumRandom VariablesFinance & Derivatives Premium
- Variance of a squared normalMediumRandom VariablesStatistics Premium
- Variance of a sum drawn without replacementMediumRandom Variables Premium
- Variance of a two-regime returnMediumRandom VariablesStatistics Premium
- Variance of an aggregate Poisson totalMediumRandom VariablesStochastic Processes Premium
- Variance of coins-per-die headsMediumRandom VariablesStatistics Premium
- When a biased estimator winsMediumRandom VariablesStatistics Premium
- Which desk books the larger dayMediumRandom VariablesStatistics Premium
- Best-of-seven underdogHardProbabilityRandom Variables Premium
- Correlation of min and maxHardProbabilityRandom Variables Premium
- Order statistics are BetaHardRandom VariablesStatistics Premium
- Ratio of two normalsHardRandom VariablesStatistics Premium
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