Re: [office-formula] BETADIST parameter Cumulative

["Andreas J. Guelzow" <aguelzow@math.concordia.ab.ca>]

On Tue, 2007-20-03 at 13:43 +0100, Eike Rathke wrote:
> Hi Andreas,
> 
> On Friday, 2007-03-16 14:30:51 -0600, Andreas J. Guelzow wrote:
> 
> > BINOMDIST, EXPONDIST, GAMMADIST, HYPGEOMDIST, NORMDIST have an optional
> > argument (in XL, gnumeric,...) to switch between cumulative and
> > non-cumulative answers.
> > 
> > Is there any reasonable justification why other ...DIST functions do not
> > have the same switch (other than well XL picked that at random).
> 
> Not really..
> 
> > It would be easy to add this optional parameter to the programs.
> 
> > Mathematically, the cumulative distribution and the density are defined
> > for all values of x, so there is no justification to have an constraint
> > such as a <= x <= b. The answer outside that range should just be 0 (or
> > 1 in the case of cumulative if b < x).
> 
> This is also what our current semantics describe.
> 
> > The question is now mathematically correct the function definitions
> > should be.
> 
> Well, as correct, exact and detailed as possible. In this case I think
> we don't miss anything, or do we?

Well, do we agree that BETADIST like the ...DIST functions above should
have an optional "cumulative" parameter?

About the constraint a <= x <= b that you suggested, what is its
purpose?

Sorry, I may have misunderstood your initial message.

Andreas

-- 
Andreas J. Guelzow, Professor
Dept. of Mathematical & Computing Sciences
Concordia University College of Alberta