Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: st: Calculating area under a curve


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: Calculating area under a curve
Date   Thu, 3 Dec 2009 17:49:28 -0000

It's kind of you to thank us all but you do not distinguish between quite different comments. 

Others can speak for themselves for Steve (Samuels) and I couldn't see why this would be interesting or useful. (Steve's at liberty to dissent if that's not his view.) In effect, you are integrating twice, as -cumul- is clearly numerical integration of the density function, even though not named as such, and you then integrate once more. 

Could you please explain why this is a good idea? 

Nick 
n.j.cox@durham.ac.uk 

Padmakumar Sivadasan

Thank you all (Martin, Philippe, Nick, Steve, Maarten, Bob) for your
valuable suggestions!

As suggested, I used -cumul- to calculate the cumulative distributions
and -integ- to calculate the area under the curve..

On Fri, Nov 27, 2009 at 8:22 AM, Padmakumar Sivadasan
<pmathru2@illinois.edu> wrote:
> Dear All,
>
> 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?

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index