Line for the server...

As the data management manual says (p. 443, Stata 10), there is no real advantage over -summ, d- for -_pctile-. Mainly, it can compute percentiles other than the standard ones obtainable from -summ, d-. You did not ask for a non-standard one, so -summ, d- may serve you just as well. The manual mentions a slight speed advantage for -_pctile- which results from the fact that -summ,d- calculates redundant (for you) information like standard deviation and mean while all you want is a specific percentile. Particularly in the case where all you want is one percentile, -_pctile- should be better. -set rmsg on- to check for yourself :-)

After -_pctile-, you will find the first percentile requested in -r(r1)- so the returned values are not as intuitively labelled as after -summ, d-.

On the second issue, do post the code in the immediate vicinity of the problem in your code.

HTH

Martin

-----Original Message-----

From:

[hidden email] [mailto:

[hidden email]] On Behalf Of Supnithadnaporn, Anupit

Sent: Wednesday, December 03, 2008 3:02 AM

To:

[hidden email]
Subject: Re: st: RE: RE: Simulation: marginal effect at the 5th percentile

Hello all,

----- "Martin Weiss" <

[hidden email]> wrote:

> On the occasion of this thread: Is capitalization in the names of

> returned results really advisable? - e(Xmfx_dydx)- may be used less frequently,

> but I remember being bitten by -r(var)- as opposed to -r(Var)- after -sum-.

> What is the benefit of a capitalized "V" here?

Thank you Martin. Your code -loc ap5 = r(p5)- after -sum a, detail- works fine.

Also, I really appreciate your careful looking at my code and finding about typos

In fact, I got an error from -r(var)- exactly like you just told me. Well, I made all the typos here because I did not copy my code exactly from my program. I try

to simplify and focus on my problem.

Also, thank you Marrten for your suggestion. I will try out your suggestion

next.

However, Martin, I have a few questions for you, please. Your answer would

help educate me about Stata programming.

1) For the 2 ways of coding, which one is faster in terms of simulating time.

Also, for the first way, -r(p5)- has a specific reference to the 5th percentile

from the -sum, detail- command, right? When I look at -r(r1)-, how and what

would this refer to?

1st way: sum a, detail

loc ap5 = r(p5)

2nd way: _pctile a, p(5)

loc ap5 = r(r1)

2) I have tried to run your suggested program (copy and paste it in the do and

run). I got an error saying

class system failure

class system failure

class system failure

class system failure

class system failure

class system failure

--more--

I did -set trace on- and see a lot of red characters in many places. Also the

-trace- output seems very long. I am not sure I should post it here.

What would be the problem here?

Thank you very much,

Anupit

PS I am using Stata SE 9 on Window Vista Home

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