Percentile
Statistical Percentile
A value below which a given percentage of observations fall (e.g. 95th percentile means 95% of values are lower).
기술 세부사항
Percentile calculations are a source of common errors: a price increase from $100 to $150 is a 50% increase, but returning from $150 to $100 is a 33.3% decrease. Percentage points differ from percentages: an interest rate moving from 2% to 3% is a 1 percentage point increase but a 50% relative increase. In computing, floating-point arithmetic can introduce rounding errors — JavaScript's 0.1 + 0.2 = 0.30000000000000004. Use integer arithmetic (cents, basis points) for financial calculations.
예시
``` Percentage calculations: What is 15% of 240? → 240 × 0.15 = 36 $80 to $100 — what % increase? → (100 - 80) / 80 × 100 = 25% Percentage point vs percentage: Rate from 4% to 6% = +2 percentage points = +50% relative increase ```