Statistics Toolbox™

fcdf - F cumulative distribution function

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. X, V1, and V2 can be vectors, matrices, or multidimensional arrays that are all 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 ν₁ and ν₂ will fall in the interval [0 x].

Examples

The following illustrates a 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, fpdf, finv, fstat, frnd

factoran

ff2n