<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
<!DOCTYPE MAN SYSTEM "../../manrev.dtd">
<MAN>
  <LANGUAGE>eng</LANGUAGE>
  <TITLE>cdff</TITLE>
  <TYPE>Scilab Function</TYPE>
  <DATE>Dec 1997</DATE>
  <SHORT_DESCRIPTION name="cdff"> cumulative distribution function F distribution</SHORT_DESCRIPTION>
  <CALLING_SEQUENCE>
    <CALLING_SEQUENCE_ITEM>[P,Q]=cdff(&quot;PQ&quot;,F,Dfn,Dfd)  </CALLING_SEQUENCE_ITEM>
    <CALLING_SEQUENCE_ITEM>[F]=cdff(&quot;F&quot;,Dfn,Dfd,P,Q);  </CALLING_SEQUENCE_ITEM>
    <CALLING_SEQUENCE_ITEM>[Dfn]=cdff(&quot;Dfn&quot;,Dfd,P,Q,F);  </CALLING_SEQUENCE_ITEM>
    <CALLING_SEQUENCE_ITEM>[Dfd]=cdff(&quot;Dfd&quot;,P,Q,F,Dfn)  </CALLING_SEQUENCE_ITEM>
  </CALLING_SEQUENCE>
  <PARAM>
    <PARAM_INDENT>
      <PARAM_ITEM>
        <PARAM_NAME>P,Q,F,Dfn,Dfd</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: five real vectors of the same size.</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>P,Q (Q=1-P)  </PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>:  The integral from 0 to F of the f-density. Input range: [0,1].</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>F</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: Upper limit of integration of the f-density. Input range: [0, +infinity). Search range: [0,1E300]</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>Dfn</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: Degrees of freedom of the numerator sum of squares. Input range: (0, +infinity). Search range: [ 1E-300, 1E300]</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
      <PARAM_ITEM>
        <PARAM_NAME>Dfd</PARAM_NAME>
        <PARAM_DESCRIPTION>
          <SP>: Degrees of freedom of the denominator sum of squares. Input range: (0, +infinity). Search range: [ 1E-300, 1E300]</SP>
        </PARAM_DESCRIPTION>
      </PARAM_ITEM>
    </PARAM_INDENT>
  </PARAM>
  <DESCRIPTION>
    <P>
    Calculates any one parameter of the F distribution
    given values for the others.</P>
    <P>
    Formula   26.6.2   of   Abramowitz   and   Stegun,  Handbook  of
    Mathematical  Functions (1966) is used to reduce the computation
    of the  cumulative  distribution function for the  F  variate to
    that of an incomplete beta.</P>
    <P>
    Computation of other parameters involve a seach for a value that
    produces  the desired  value  of P.   The search relies  on  the
    monotinicity of P with the other parameter.</P>
    <P>
    The value of the  cumulative  F distribution is  not necessarily
    monotone in  either degrees of freedom.  There  thus may  be two
    values  that  provide a given CDF  value.   This routine assumes
    monotonicity and will find an arbitrary one of the two values.</P>
    <P>
    From DCDFLIB: Library of Fortran Routines for Cumulative Distribution
    Functions, Inverses, and Other Parameters (February, 1994)
    Barry W. Brown, James Lovato and Kathy Russell. The University of
    Texas.</P>
  </DESCRIPTION>
</MAN>
