Y = ncfpdf(X,NU1,NU2,DELTA) computes the noncentral F pdf at each of the values in X using the corresponding numerator degrees of freedom in NU1, denominator degrees of freedom in NU2, and positive noncentrality parameters in DELTA. X, NU1, N2, and B can be vectors, matrices, or multidimensional arrays that all have the same size, which is also the size of Y. A scalar input for P, NU1, NU2, or DELTA is expanded to a constant array with the same dimensions as the other inputs.

The F distribution is a special case of the noncentral F where δ = 0. As δ increases, the distribution flattens like the plot in the example.

Examples

Compare the noncentral F pdf with δ = 10 to the F pdf with the same number of numerator and denominator degrees of freedom (5 and 20 respectively).

x = (0.01:0.1:10.01)';
p1 = ncfpdf(x,5,20,10);
p = fpdf(x,5,20);
plot(x,p,'-',x,p1,'-')

References

[1] Johnson, N., and S. Kotz. Distributions in Statistics: Continuous Univariate Distributions-2. Hoboken, NJ: John Wiley & Sons, Inc., 1970, pp. 189–200.

ncfpdf - Noncentral F probability density function

Syntax

Description

Examples

References

See Also

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