Cauchy distribution

E239287

The Cauchy distribution is a continuous probability distribution with heavy tails and undefined mean and variance, often used as a classic example of pathological behavior in probability theory and statistics.

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All labels observed (3)

Statements (53)

Predicate Object
instanceOf continuous probability distribution
heavy-tailed distribution
probability distribution
stable distribution
univariate distribution
belongsToFamily location–scale family
correspondsToStudentTWithDegreesOfFreedom 1
definedOn real line
hasAllMoments do not exist
hasAlternativeName Cauchy distribution
surface form: Breit–Wigner distribution

Cauchy distribution
surface form: Lorentz distribution
hasCharacteristicFunction φ(t) = exp(i x0 t - γ |t|)
hasConvolutionProperty sum of independent Cauchy variables is Cauchy
hasCumulativeDistributionFunction F(x) = 1/π arctan(x) + 1/2
F(x; x0, γ) = 1/π arctan((x - x0)/γ) + 1/2
hasEntropy H = ln(4πγ)
hasHazardFunction h(x) = f(x) / (1 - F(x)) for x in ℝ
hasKurtosis undefined
hasLocationParameter 0
x0
hasMean undefined
hasMedian x0
hasMedianAbsoluteDeviation γ
hasMode x0
hasMomentGeneratingFunction does not exist
hasProbabilityDensityFunction f(x) = 1 / [π (1 + x^2)]
f(x; x0, γ) = 1 / [πγ (1 + ((x - x0)/γ)^2)]
hasQuantileFunction Q(p) = x0 + γ tan[π(p - 1/2)]
hasScaleParameter 1
γ
hasSkewness 0
hasStabilityIndex 1
hasStandardForm standard Cauchy distribution
hasSupport (-∞, ∞)
hasTailBehavior f(x) ~ 1/(πγ) · 1/x^2 as |x| → ∞
hasVariance undefined
isHeavyTailed true
isLevyAlphaStable true
isSpecialCaseOf Lévy alpha-stable distribution
Pearson distribution
surface form: Pearson type VII distribution

Student’s t-distribution
surface form: Student's t-distribution

generalized hyperbolic distribution
q-Gaussian distribution
isStable true
isSymmetricAbout x0
isUsedAs example of distribution with undefined mean
example of distribution with undefined variance
example of pathological behavior in probability theory
heavy-tailed prior distribution
isUsedIn Bayesian inference
surface form: Bayesian statistics

robust statistics
namedAfter Augustin-Louis Cauchy
requiresScaleParameterCondition γ > 0

Referenced by (5)

Full triples — surface form annotated when it differs from this entity's canonical label.

Augustin-Louis Cauchy knownFor Cauchy distribution
Augustin-Louis notableFor Cauchy distribution
subject surface form: Augustin-Louis Cauchy
Cauchy distribution hasAlternativeName Cauchy distribution
this entity surface form: Lorentz distribution
Cauchy distribution hasAlternativeName Cauchy distribution
this entity surface form: Breit–Wigner distribution
Tukey's lambda distribution approximates Cauchy distribution