Evaluates the F cumulative probability distribution function.

Parameters

x

A double specifying the argument at which the function is to be evaluated.

dfn

A double specifying the numerator degrees of freedom. It must be positive.

dfd

A double specifying the denominator degrees of freedom. It must be positive.

Return Value

A double specifying the probability that an F random variable takes on a value less than or equal to x

Remarks

F evaluates the distribution function of a Snedecor's F random variable with dfn numerator degrees of freedom and dfd denominator degrees of freedom. The function is evaluated by making a transformation to a beta random variable and then using the function Beta. If X is an F variate with and degrees of freedom and , then Y is a beta variate with parameters and . F also uses a relationship between F random variables that can be expressed as follows:

For greater right tail accuracy, Cdf.ComplementaryF.

See Also

Cdf Class | Imsl.Stat Namespace | Example

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