Statistics Toolbox™

chi2cdf - Chi-square cumulative distribution function

Syntax

P = chi2cdf(X,V)

Description

P = chi2cdf(X,V) computes the chi-square cdf at each of the values in X using the corresponding parameters in V. X and V can be vectors, matrices, or multidimensional arrays that have the same size. A scalar input is expanded to a constant array with the same dimensions as the other input.

The degrees of freedom parameters in V must be positive integers, and the values in X must lie on the interval [0 Inf].

The χ² cdf for a given value x and degrees-of-freedom ν is

where Γ( · ) is the Gamma function.

The chi-square density function with ν degrees-of-freedom is the same as the gamma density function with parameters ν/2 and 2.

Examples

probability = chi2cdf(5,1:5)
probability =
  0.9747  0.9179  0.8282  0.7127  0.5841

probability = chi2cdf(1:5,1:5)
probability =
  0.6827  0.6321  0.6084  0.5940  0.5841

See Also

cdf, chi2pdf, chi2inv, chi2stat, chi2rnd

cdfplot

chi2gof