Sample Size Interview Questions
Sample size interview questions for precision, power, variance, detectable effects, experiment cost, and root-n intuition.
Candidates who need intuition for precision, power, and experiment design.
Sample size affects precision
Under standard independent-sample assumptions, larger sample size reduces standard error for many estimates and makes noise less dominant.
Root-n is the key intuition
Standard error often shrinks like one over square root of n. Getting twice as precise can require about four times as much data.
Concrete example
If sample size rises from 100 to 400, standard error can roughly halve under the simple root-n relationship, provided the observations behave similarly.
Balance cost and benefit
More data can be expensive or slow. A good answer discusses whether the extra precision changes the decision enough to justify the delay.
Common mistakes
Candidates often ask for more data without saying what precision or power problem it solves. Tie sample size to the goal.
Practice the pattern
Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.