Ρρ
MATHEMATICS
- Radial coordinate ρ (sometimes).
- Parameter/constant in equations.
PROBABILITY
- Density/measure in some contexts (ρ).
- Can appear as a dependence parameter.
STATISTICS
- Population correlation (ρ).
- Spearman's ρ (rank correlation).
PRONUNCIATION
- Ancient Greek
- sound [r]
- Modern Greek
- ρο [ro] · sound [r]
IN FORMULAS
- ρ = Cov(X, Y) / (σₓ σᵧ)The population correlation between X and Y.See it explained at morrisonkuhlsen.com →
- ρₛ = 1 − 6 Σ dᵢ² / (n(n² − 1))Spearman's rank correlation (without ties).See it explained at morrisonkuhlsen.com →
HOW TO WRITE IT — click to copy
lowercase
variant
uppercasesame as the Latin letter: LaTeX has no command for it
DON'T CONFUSE IT
- ρ p φ β In ρ the stem grows out of the bowl in one curve; the Latin p has a separate straight stem.
Note: notations vary between books/fields; these are the most common usages.