Statistics Toolbox

fcdf

F cumulative distribution function (cdf)

Syntax

• P = fcdf(X,V1,V2)
  

Description

P = fcdf(X,V1,V2) computes the F cdf at each of the values in X using the corresponding parameters in V1 and V2. Vector or matrix inputs for X, V1, and V2 must all be the same size. A scalar input is expanded to a constant matrix with the same dimensions as the other inputs. The parameters in V1 and V2 must be positive integers.

The F cdf is

The result, p, is the probability that a single observation from an F distribution with parameters ₁ and ₂ will fall in the interval [0 x].

Examples

This example illustrates an important and useful mathematical identity for the F distribution.

• nu1 = 1:5;
  nu2 = 6:10;
  x = 2:6;
  F1 = fcdf(x,nu1,nu2)
  F1 =
      0.7930    0.8854    0.9481    0.9788    0.9919
  F2 = 1 - fcdf(1./x,nu2,nu1)
  F2 =
      0.7930    0.8854    0.9481    0.9788    0.9919
  

See Also

cdf, finv, fpdf, frnd, fstat

factoran

ff2n