# Re: st: RE: AW: Calculating area under a curve

 From sjsamuels@gmail.com To statalist@hsphsun2.harvard.edu Subject Re: st: RE: AW: Calculating area under a curve Date Fri, 27 Nov 2009 14:03:33 -0500

```Although areas under the cumulative probability curve F(t) are
meaningless as far as I know,  the total area under the survival curve
S(t) = 1 - F(t)  is equal to the mean.

-Steve

On Fri, Nov 27, 2009 at 12:15 PM, Nick Cox <n.j.cox@durham.ac.uk> wrote:
> Just to point out that -cumul- gives you the (cumulated) area under the density function. That's what a distribution function is. I don't see why you would want to integrate again.
>
> Nick
> n.j.cox@durham.ac.uk
>
> Martin Weiss
>
> Would the -qqplot- recently advertised by NJC not be a good alternative? See
> http://www.stata.com/statalist/archive/2009-11/msg01157.html
>
>
> I am analyzing the performance of companies indicated by a variable
> v1. Variable v1 has a range 0-10 where higher values indicate poorer
> performance.  I am attempting to compare the performance of companies
> for the country as a whole and to that at the local level
> (Metropolitan Statistical Area). I am interested not only in the mean
> value of v1 but also the variability of v1. One suggestion I got was
> to compute the cumulative probabilities at the national and local
> levels and then compare the area under the cumulative probability
> distributions at the local level to that at the national level.
>
> I understand that I can use the -cumul- function in Stata to calculate
> the cumulative probabilities but I couldn't find a method to calculate
> the area under the cumulative probability curve. I have two questions
> in this regard
> (1) Is there a way in Stata to calculate the area under cumulative
> probability curve?
> (2) Could someone point me to reference that I can use to read up on
> this method?
>
>
> *
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>

--
Steven Samuels
sjsamuels@gmail.com
18 Cantine's Island
Saugerties NY 12477
USA
845-246-0774

*
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```