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RE: st: RE: How to find Max value.


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: RE: How to find Max value.
Date   Sat, 19 Jun 2004 20:36:00 +0100

Ah! I think I misunderstood this. Sorry. 

Assuming also an identifier variable 
-id-, perhaps what you want is more like

egen group = group(temp time), label 
egen max = max(mf), by(id) 
tab group if max == mf 

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

> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu]On Behalf Of Nick Cox
> Sent: 19 June 2004 20:23
> To: statalist@hsphsun2.harvard.edu
> Subject: RE: st: RE: How to find Max value.
> 
> 
> Thank you for the further detail. However, 
> if I understand correctly, you are asking a 
> very strange question here. Since -mf- 
> (presumably -rf- is the same thing or similar) 
> is measured to 1 or 2 decimal 
> places, the maximum is quite likely to be unique 
> for each subset (time and temperature), and the percent equal to the 
> maximum will just be 100 / number in subset. 
> Fortuitously, you may get tied values, but 
> it is difficult to believe that their frequency 
> would reflect properties of statistical 
> or scientific interest. In addition, if you attempt 
> to count how many values are equal to the maximum, 
> you are likely to run into the precision problems 
> detailed at [U] 16.10. 
> 
> Providing Stata code would just be giving 
> you the means of doing something bizarre, 
> I believe. 
> 
> Nick 
> n.j.cox@durham.ac.uk 
> 
> Syed O Masood
>  
> > I have put a piece of data below. 
> > I need to find what percent of people have maximum
> > value in the variable rf at time 1 and temp 26, what
> > percent of people will have maximum value of mf at
> > time 2 and temp 26, what percent of people have max
> > value of mf at time 3 and temp 26 and similarly for
> > tmep 35oC. 
> > 
> > Thanks in advance for your help & support
> >  
> > . list temp time mf
> > 
> >      +---------------------+
> >      | temp   time      mf |
> >      |---------------------|
> >   1. |   26      1     5.5 |
> >   2. |   26      2    8.64 |
> >   3. |   26      3   12.03 |
> >   4. |   35      1    8.64 |
> >   5. |   35      2    5.59 |
> >      |---------------------|
> >   6. |   35      3    9.02 |
> >   7. |   26      1    3.88 |
> >   8. |   26      2    8.63 |
> >   9. |   26      3   10.35 |
> >  10. |   35      1    8.34 |
> >      |---------------------|
> >  11. |   35      2   10.22 |
> >  12. |   35      3   11.25 |
> >  13. |   26      1    3.29 |
> >  14. |   26      2    6.12 |
> >  15. |   26      3    7.37 |
> >      |---------------------|
> > 
> > --- Nick Cox <n.j.cox@durham.ac.uk> wrote:
> > > This isn't very clear to me. What percent 
> > > of anything is equal to the maximum value 
> > > is very sensitive to the resolution of measurement, 
> > > and as such doesn't seem a very obvious 
> > > thing to calculate. 
> > > 
> > > You may get a better answer if you give 
> > > an example table showing some data. 
> > > 
> > > Nick 
> > > n.j.cox@durham.ac.uk 
> 
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