### Navigation

- index
- modules |
- modules |
- next |
- previous |
- SciPy v0.12 Reference Guide (DRAFT) »
- Special functions (`scipy.special`) »

# scipy.special.fdtr

`scipy.special.``fdtr`(x1, x2, x3[, out]) = <ufunc 'fdtr'>

  y=fdtr(dfn,dfd,x) returns the area from zero to x under the F density function (also known as Snedcor’s density or the variance ratio density). This is the density of X = (unum/dfn)/(uden/dfd), where unum and uden are random variables having Chi square distributions with dfn and dfd degrees of freedom, respectively.

### Navigation

- index
- modules |
- modules |
- next |
- previous |
- SciPy v0.12 Reference Guide (DRAFT) »
- Special functions (`scipy.special`) »