# Difference between revisions of "Manuals/calci/FDIST"

FDIST(x,df1,df2)

• is the value of the function
• and is degrees of freedom.

## Description

• This function gives the value of F probability distribution.
• This distribution is continuous probability distribution and it is called Fisher-Snedecor distribution.
• The F distribution is an asymmetric distribution that has a minimum value of 0, but no maximum value.
• In is the value of the function , is the numerator degrees of freedom and is the denominator degrees of freedom.
• This distribution is the ratio of two chi-square distributions with degrees of freedom r1 and r2, respectively, where each chi-square has first been divided by its degrees of freedom.
• The Probability density function of the F distribution is:  where is the Gamma Function.

• The gamma function is defined by [itex]\Gamma(t) = \int\limits_{0}^{infty} x^{t-1} e^{-x} dx/math>.

When the value of df1 and df2 are not integers ,then it is converted in to integers.

• This function will give the result as error when
 1. any one of the argument is nonnumeric.
2.x is negative
3. df1 or df2<1 ,and  df1 ordf2>=10^10


## Examples

1. FDIST(20.6587,7,3)=0.01526530981
2. FDIST(70.120045,12.2,6.35)=0.000011229898
3. FDIST(10,1.3,1.5)=0.134947329626
4. FDIST(-28,4,6)=NAN