// QUANT INTERVIEW PREP
Statistics Quant Interview Prep & Practice
Quant research screens test whether you can read data: what a distribution implies, what a regression says and does not say, and when a result is noise.
Sample Statistics Questions
Question 1 · SIG Quantitative Evaluation
60 independent attempts, each succeeding 12% of the time. How many successes do you expect?
See the solution ↓Question 2 · Five Rings Quant Trading Screen
How many observations are needed for a 95% confidence interval of half-width 1, when the standard deviation is 23?
See the solution ↓Question 3 · Mako Aptitude and Round Two
A normal variable has mean 50 and standard deviation 5. What share of values exceed 65?
- 49.9%
- 99.7%
- 0.3%
- 0.1%
Question 4 · Wincent Online Problems
A fair coin is flipped 8 times. What is the chance of at least 7 heads, as a percentage?
See the solution ↓Question 5 · DRW Quantitative Challenge
Returns of stock Y regress on returns of index X. The correlation is 0.6, the standard deviation of Y is 4%, and of X is 2%. What is the regression slope?
- 0.6
- 2.4
- 1.2
- 0.3
Step-by-Step Solutions
Solution 1
60 independent attempts, each succeeding 12% of the time. How many successes do you expect?
Answer: 7.2
60 × 0.12 = 7.2. Independence does not change the mean, only the spread.
Solution 2
How many observations are needed for a 95% confidence interval of half-width 1, when the standard deviation is 23?
Answer: 2033
n = (1.96σ/w)². Call it 2: (2 × 23/1)² = 2,116, which overshoots by 4%.
Solution 3
A normal variable has mean 50 and standard deviation 5. What share of values exceed 65?
Answer: 0.1%
65 is 3 standard deviations above the mean. About 99.7% sits inside that band, leaving 0.3% in both tails and 0.1% in the upper one.
Solution 4
A fair coin is flipped 8 times. What is the chance of at least 7 heads, as a percentage?
Answer: 3.5
The counts from 7 to 8 are 8 + 1 = 9, out of 2^8 = 256, so 3.5%.
Solution 5
Returns of stock Y regress on returns of index X. The correlation is 0.6, the standard deviation of Y is 4%, and of X is 2%. What is the regression slope?
Answer: 1.2
β = r·(σy/σx) = 0.6·4/2 = 1.2. Correlation alone is the unitless version - the slope re-attaches the scales.
How to Pass the Statistics Screen
Know the standard distributions by their shape and their moments. Most questions are a binomial, Poisson or normal in disguise.
Read a regression coefficient with its standard error. A slope means nothing until you know how many standard errors it sits from zero.
Ask how the sample was chosen. Selection effects and multiple testing explain more surprising results than real effects do.
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