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st: Need to Title a Second Y-Axis...

Ploutz-Snyder, Robert (JSC-SK)[USRA]
Statlisisters,

I'm unsuccessful at applying axis title to a SECOND Y-axis on a plot..  Here's what I'm trying:

twoway line y1  X,  sort by(group) ||line y2 X, xtitle("Time") ytitle("Predicted y1") yaxis(2) ytitle("Predicted y2",axis(2))  sort

I can get the second Y axis to show up, and can manipulate options with it (ex. can change labels), but I cannot get the second axis TITLE to appear??  What am I doing wrong??

Thanks!

********************************************************************************************
Rob
 



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st: AW: Need to Title a Second Y-Axis...

Martin Weiss-5

<>

Does work, though...

*************
sysuse uslifeexp, clear

 twoway (line le_wmale year) /*
 */ (line le_bmale year, yaxis(2)),/*
 */  ytitle(Left Side)/*
 */  ytitle(Right Side, axis(2))
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: [hidden email]
[mailto:[hidden email]] Im Auftrag von Ploutz-Snyder,
Robert (JSC-SK)[USRA]
Gesendet: Mittwoch, 10. Juni 2009 15:32
An: [hidden email]
Betreff: st: Need to Title a Second Y-Axis...

Statlisisters,

I'm unsuccessful at applying axis title to a SECOND Y-axis on a plot..
Here's what I'm trying:

twoway line y1  X,  sort by(group) ||line y2 X, xtitle("Time")
ytitle("Predicted y1") yaxis(2) ytitle("Predicted y2",axis(2))  sort

I can get the second Y axis to show up, and can manipulate options with it
(ex. can change labels), but I cannot get the second axis TITLE to appear??
What am I doing wrong??

Thanks!

****************************************************************************
****************
Rob
 



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Re: st: Need to Title a Second Y-Axis...

Maarten buis
In reply to this post by Ploutz-Snyder, Robert (JSC-SK)[USRA]

--- On Wed, 10/6/09, Ploutz-Snyder, Robert wrote:
> I'm unsuccessful at applying axis title to a SECOND Y-axis
> on a plot..  Here's what I'm trying:
>
> twoway line y1  X,  sort by(group) ||line y2 X,
> xtitle("Time") ytitle("Predicted y1") yaxis(2)
> ytitle("Predicted y2",axis(2))  sort

--- On Wed, 10/6/09, Martin Weiss wrote:

> Does work, though...
>
> *************
> sysuse uslifeexp, clear
>
> twoway (line le_wmale year) /*
> */ (line le_bmale year, yaxis(2)),/*
> */  ytitle(Left Side)/*
> */  ytitle(Right Side, axis(2))
> *************

The problem is the -by()- option:

*---------- begin example --------
sysuse auto, clear
twoway scatter price mpg || ///
       scatter turn mpg,    ///
       by(foreign) yaxis(2)  ///
       ytitle("turn", axis(2))
*---------- end example -----------

Don't see an immediate solution though
(have to leave now for a seminar).

-- Maarten

-----------------------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


     

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st: RE: AW: Need to Title a Second Y-Axis...

Ploutz-Snyder, Robert (JSC-SK)[USRA]
In reply to this post by Martin Weiss-5
Hmmm.. I'm using a few more options (scale, legend, etc) and I can't make that work either Martin.  I tried to simplify my code earlier, but here's my full code including the other options I'm throwing at Stata:


twoway (line y1  x  if followup==0,  sort by(tmt)   xlabel(0 1(1)12) xtitle("Treatment Weeks"))  (line y2  x if followup==0, yaxis(2) sort by(tmt) ytitle("LEFT axis title ")  ytitle("RIGHT axis title", axis(2))  ylabel(0 1(1)3)  ylabel(0(.1)1,axis(2)) legend(label(1 "left legend title ") label(2 "right legend title)")))

I'm guessing there's something about the order of these options??  I tried moving the xlabel and xtitle at the END with all of the other options (my usual method), but that doesn't seem to work.  I moved things all around hoping to "bump into" the right order, but I'm stumped..

Thanks!
Rob




-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Martin Weiss
Sent: Wednesday, June 10, 2009 8:51 AM
To: [hidden email]
Subject: st: AW: Need to Title a Second Y-Axis...


<>

Does work, though...

*************
sysuse uslifeexp, clear

 twoway (line le_wmale year) /*
 */ (line le_bmale year, yaxis(2)),/*
 */  ytitle(Left Side)/*
 */  ytitle(Right Side, axis(2))
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: [hidden email]
[mailto:[hidden email]] Im Auftrag von Ploutz-Snyder,
Robert (JSC-SK)[USRA]
Gesendet: Mittwoch, 10. Juni 2009 15:32
An: [hidden email]
Betreff: st: Need to Title a Second Y-Axis...

Statlisisters,

I'm unsuccessful at applying axis title to a SECOND Y-axis on a plot..
Here's what I'm trying:

twoway line y1  X,  sort by(group) ||line y2 X, xtitle("Time")
ytitle("Predicted y1") yaxis(2) ytitle("Predicted y2",axis(2))  sort

I can get the second Y axis to show up, and can manipulate options with it
(ex. can change labels), but I cannot get the second axis TITLE to appear??
What am I doing wrong??

Thanks!

****************************************************************************
****************
Rob
 



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AW: st: Need to Title a Second Y-Axis...

Martin Weiss-5
In reply to this post by Maarten buis

<>

Maarten and Robert do have a case. I cannot make the title appear on a -by- graph, either, even with the help of the dialog box.

*************
sysuse uslifeexp, clear

gen byte dummy=_n>`=_N/2'

twoway (line le_male year)/*
 */  (line le_female year, yaxis(2)), /*
 */ ytitle(Left Side) ytitle(Right Side, axis(2))/*
 */  by(dummy)
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Maarten buis
Gesendet: Mittwoch, 10. Juni 2009 16:11
An: [hidden email]
Betreff: Re: st: Need to Title a Second Y-Axis...


--- On Wed, 10/6/09, Ploutz-Snyder, Robert wrote:
> I'm unsuccessful at applying axis title to a SECOND Y-axis
> on a plot..  Here's what I'm trying:
>
> twoway line y1  X,  sort by(group) ||line y2 X,
> xtitle("Time") ytitle("Predicted y1") yaxis(2)
> ytitle("Predicted y2",axis(2))  sort

--- On Wed, 10/6/09, Martin Weiss wrote:

> Does work, though...
>
> *************
> sysuse uslifeexp, clear
>
> twoway (line le_wmale year) /*
> */ (line le_bmale year, yaxis(2)),/*
> */  ytitle(Left Side)/*
> */  ytitle(Right Side, axis(2))
> *************

The problem is the -by()- option:

*---------- begin example --------
sysuse auto, clear
twoway scatter price mpg || ///
       scatter turn mpg,    ///
       by(foreign) yaxis(2)  ///
       ytitle("turn", axis(2))
*---------- end example -----------

Don't see an immediate solution though
(have to leave now for a seminar).

-- Maarten

-----------------------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


     

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RE: st: Need to Title a Second Y-Axis...

Ploutz-Snyder, Robert (JSC-SK)[USRA]
Ok.. so I'm not going crazy then.
I did discover that if you go into the chart editor tool, double click on the right axis, then click the "Title" button, then select the "Advanced" Tab and UNCHECK the box for "hide text box," the title from my code magically appears.

So if someone can figure out how to turn off the default function of  hiding the text box on the second Y-axis title, that should do it??

Thanks for solidifying my sanity on this one!
Rob

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Martin Weiss
Sent: Wednesday, June 10, 2009 9:31 AM
To: [hidden email]
Subject: AW: st: Need to Title a Second Y-Axis...


<>

Maarten and Robert do have a case. I cannot make the title appear on a -by- graph, either, even with the help of the dialog box.

*************
sysuse uslifeexp, clear

gen byte dummy=_n>`=_N/2'

twoway (line le_male year)/*
 */  (line le_female year, yaxis(2)), /*
 */ ytitle(Left Side) ytitle(Right Side, axis(2))/*
 */  by(dummy)
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Maarten buis
Gesendet: Mittwoch, 10. Juni 2009 16:11
An: [hidden email]
Betreff: Re: st: Need to Title a Second Y-Axis...


--- On Wed, 10/6/09, Ploutz-Snyder, Robert wrote:
> I'm unsuccessful at applying axis title to a SECOND Y-axis
> on a plot..  Here's what I'm trying:
>
> twoway line y1  X,  sort by(group) ||line y2 X,
> xtitle("Time") ytitle("Predicted y1") yaxis(2)
> ytitle("Predicted y2",axis(2))  sort

--- On Wed, 10/6/09, Martin Weiss wrote:

> Does work, though...
>
> *************
> sysuse uslifeexp, clear
>
> twoway (line le_wmale year) /*
> */ (line le_bmale year, yaxis(2)),/*
> */  ytitle(Left Side)/*
> */  ytitle(Right Side, axis(2))
> *************

The problem is the -by()- option:

*---------- begin example --------
sysuse auto, clear
twoway scatter price mpg || ///
       scatter turn mpg,    ///
       by(foreign) yaxis(2)  ///
       ytitle("turn", axis(2))
*---------- end example -----------

Don't see an immediate solution though
(have to leave now for a seminar).

-- Maarten

-----------------------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


     

*
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*   http://www.stata.com/help.cgi?search
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*   http://www.ats.ucla.edu/stat/stata/


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AW: st: Need to Title a Second Y-Axis...

Martin Weiss-5

<>

This takes you halfway there:

*************
sysuse uslifeexp, clear
gen dummy=_n>`=_N/2'
tw (line le_male year)/*
 */  (line le_female year, yaxis(2)),/*
 */  by(dummy, iytitle)
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Ploutz-Snyder, Robert (JSC-SK)[USRA]
Gesendet: Mittwoch, 10. Juni 2009 16:39
An: [hidden email]
Betreff: RE: st: Need to Title a Second Y-Axis...

Ok.. so I'm not going crazy then.
I did discover that if you go into the chart editor tool, double click on the right axis, then click the "Title" button, then select the "Advanced" Tab and UNCHECK the box for "hide text box," the title from my code magically appears.

So if someone can figure out how to turn off the default function of  hiding the text box on the second Y-axis title, that should do it??

Thanks for solidifying my sanity on this one!
Rob

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Martin Weiss
Sent: Wednesday, June 10, 2009 9:31 AM
To: [hidden email]
Subject: AW: st: Need to Title a Second Y-Axis...


<>

Maarten and Robert do have a case. I cannot make the title appear on a -by- graph, either, even with the help of the dialog box.

*************
sysuse uslifeexp, clear

gen byte dummy=_n>`=_N/2'

twoway (line le_male year)/*
 */  (line le_female year, yaxis(2)), /*
 */ ytitle(Left Side) ytitle(Right Side, axis(2))/*
 */  by(dummy)
*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Maarten buis
Gesendet: Mittwoch, 10. Juni 2009 16:11
An: [hidden email]
Betreff: Re: st: Need to Title a Second Y-Axis...


--- On Wed, 10/6/09, Ploutz-Snyder, Robert wrote:
> I'm unsuccessful at applying axis title to a SECOND Y-axis
> on a plot..  Here's what I'm trying:
>
> twoway line y1  X,  sort by(group) ||line y2 X,
> xtitle("Time") ytitle("Predicted y1") yaxis(2)
> ytitle("Predicted y2",axis(2))  sort

--- On Wed, 10/6/09, Martin Weiss wrote:

> Does work, though...
>
> *************
> sysuse uslifeexp, clear
>
> twoway (line le_wmale year) /*
> */ (line le_bmale year, yaxis(2)),/*
> */  ytitle(Left Side)/*
> */  ytitle(Right Side, axis(2))
> *************

The problem is the -by()- option:

*---------- begin example --------
sysuse auto, clear
twoway scatter price mpg || ///
       scatter turn mpg,    ///
       by(foreign) yaxis(2)  ///
       ytitle("turn", axis(2))
*---------- end example -----------

Don't see an immediate solution though
(have to leave now for a seminar).

-- Maarten

-----------------------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany

http://home.fsw.vu.nl/m.buis/
-----------------------------------------


     

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*   http://www.ats.ucla.edu/stat/stata/


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st: test difference in quintiles

Susanne Neckermann
Hi!

I want to test whether the difference in the fifth percentile of two  
distributions is significant.
In principle, this test should be similar to the "median" (thats the  
name of the command) test already implemented in Stata, but  
unfortunately I cannot program .ado files and I could not find a user-
written procedure.
Any idea how to go about this?
P.S. the number of observations in the fifth percentile is pretty low  
(around 6), so one might have to use something with bootstrap or  
permutations.

Thank you so much in advance
susanne



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Re: st: test difference in quintiles

Tirthankar Chakravarty
<>

This is a variation of previous advice:
http://www.stata.com/statalist/archive/2009-05/msg00311.html

I believe you want to test the significance of the difference of the
5th percentile for two variables using a bootstrap. If this is the
case, then the code below applies:

/* Bootstrap the difference of percentiles */
clear
webuse nlswork, clear
keep idcode year ttl_exp
reshape wide ttl_exp, i(idcode) j(year)

cap prog drop pctile_bs
program define pctile_bs, rclass
        version 10
        syntax varlist(max=2 min=2) [if] [in]
        marksample touse
        tokenize `varlist'
        local first `1'
        macro shift
        local second `*'
        _pctile `first' if `touse', percentiles(5)
        scalar pc1 = r(r1)
        _pctile `second' if `touse', percentiles(5)
        scalar pc2 = r(r1)
        return scalar dpc = pc1-pc2
        ereturn post, esample(`touse')
end
bootstrap  Dpc = r(dpc), reps(2000) dots: pctile_bs ttl_exp68 ttl_exp69
/* End */

Please also see the reference about pivotal statistics in a bootstrap
from the previous message.

T


On Wed, Jun 10, 2009 at 3:57 PM, Susanne
Neckermann<[hidden email]> wrote:

> Hi!
>
> I want to test whether the difference in the fifth percentile of two
> distributions is significant.
> In principle, this test should be similar to the "median" (thats the name of
> the command) test already implemented in Stata, but unfortunately I cannot
> program .ado files and I could not find a user-written procedure.
> Any idea how to go about this?
> P.S. the number of observations in the fifth percentile is pretty low
> (around 6), so one might have to use something with bootstrap or
> permutations.
>
> Thank you so much in advance
> susanne
>
>
>
> *
> *   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/
>



--
To every ω-consistent recursive class κ of formulae there correspond
recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
belongs to Flg(κ) (where v is the free variable of r).

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Re: st: test difference in quintiles

Susanne Neckermann
Dear T

thank you very much for the message!!
I am a real beginner with Stata and I have to admit that I do not  
quite understand how to transfer the code to my case.
I have a variable X that I observe under two conditions Y and Z. I  
want to see if the fifth percentile of variable X in condition Y is  
different from the fifth percentile of X in condition Z.

Thank you so much for your input!!
Best
Susanne

On 10-Jun-09, at 5:26 PM, Tirthankar Chakravarty wrote:

> <>
>
> This is a variation of previous advice:
> http://www.stata.com/statalist/archive/2009-05/msg00311.html
>
> I believe you want to test the significance of the difference of the
> 5th percentile for two variables using a bootstrap. If this is the
> case, then the code below applies:
>
> /* Bootstrap the difference of percentiles */
> clear
> webuse nlswork, clear
> keep idcode year ttl_exp
> reshape wide ttl_exp, i(idcode) j(year)
>
> cap prog drop pctile_bs
> program define pctile_bs, rclass
> version 10
> syntax varlist(max=2 min=2) [if] [in]
> marksample touse
> tokenize `varlist'
> local first `1'
> macro shift
> local second `*'
> _pctile `first' if `touse', percentiles(5)
> scalar pc1 = r(r1)
> _pctile `second' if `touse', percentiles(5)
> scalar pc2 = r(r1)
> return scalar dpc = pc1-pc2
> ereturn post, esample(`touse')
> end
> bootstrap  Dpc = r(dpc), reps(2000) dots: pctile_bs ttl_exp68  
> ttl_exp69
> /* End */
>
> Please also see the reference about pivotal statistics in a bootstrap
> from the previous message.
>
> T
>
>
> On Wed, Jun 10, 2009 at 3:57 PM, Susanne
> Neckermann<[hidden email]> wrote:
>> Hi!
>>
>> I want to test whether the difference in the fifth percentile of two
>> distributions is significant.
>> In principle, this test should be similar to the "median" (thats  
>> the name of
>> the command) test already implemented in Stata, but unfortunately I  
>> cannot
>> program .ado files and I could not find a user-written procedure.
>> Any idea how to go about this?
>> P.S. the number of observations in the fifth percentile is pretty low
>> (around 6), so one might have to use something with bootstrap or
>> permutations.
>>
>> Thank you so much in advance
>> susanne
>>
>>
>>
>> *
>> *   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/
>>
>
>
>
> --
> To every ω-consistent recursive class κ of formulae there correspond
> recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
> belongs to Flg(κ) (where v is the free variable of r).
>
> *
> *   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/


*
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AW: st: test difference in quintiles

Martin Weiss-5

<>

Try:

*************
clear*
set obs 10000
capt prog drop differ

gen x= rnormal()

/*no systematic difference btw
groups
THIS IS equivalent to your
Y and Z conditions*/
gen condition=runiform()<0.5

pr differ, rclass
        vers 10.1
        qui su x if /*
 */ condition==0,/*
 */ det
 loc first=r(p5)
 qui su x if /*
 */ condition==1,/*
 */ det
 ret sca diff = r(p5)-`first'
end

bs diff=r(diff), /*
 */ reps(200): differ

*************



HTH
Martin


-----Ursprüngliche Nachricht-----
Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Susanne Neckermann
Gesendet: Mittwoch, 10. Juni 2009 17:38
An: [hidden email]
Betreff: Re: st: test difference in quintiles

Dear T

thank you very much for the message!!
I am a real beginner with Stata and I have to admit that I do not  
quite understand how to transfer the code to my case.
I have a variable X that I observe under two conditions Y and Z. I  
want to see if the fifth percentile of variable X in condition Y is  
different from the fifth percentile of X in condition Z.

Thank you so much for your input!!
Best
Susanne

On 10-Jun-09, at 5:26 PM, Tirthankar Chakravarty wrote:

> <>
>
> This is a variation of previous advice:
> http://www.stata.com/statalist/archive/2009-05/msg00311.html
>
> I believe you want to test the significance of the difference of the
> 5th percentile for two variables using a bootstrap. If this is the
> case, then the code below applies:
>
> /* Bootstrap the difference of percentiles */
> clear
> webuse nlswork, clear
> keep idcode year ttl_exp
> reshape wide ttl_exp, i(idcode) j(year)
>
> cap prog drop pctile_bs
> program define pctile_bs, rclass
> version 10
> syntax varlist(max=2 min=2) [if] [in]
> marksample touse
> tokenize `varlist'
> local first `1'
> macro shift
> local second `*'
> _pctile `first' if `touse', percentiles(5)
> scalar pc1 = r(r1)
> _pctile `second' if `touse', percentiles(5)
> scalar pc2 = r(r1)
> return scalar dpc = pc1-pc2
> ereturn post, esample(`touse')
> end
> bootstrap  Dpc = r(dpc), reps(2000) dots: pctile_bs ttl_exp68  
> ttl_exp69
> /* End */
>
> Please also see the reference about pivotal statistics in a bootstrap
> from the previous message.
>
> T
>
>
> On Wed, Jun 10, 2009 at 3:57 PM, Susanne
> Neckermann<[hidden email]> wrote:
>> Hi!
>>
>> I want to test whether the difference in the fifth percentile of two
>> distributions is significant.
>> In principle, this test should be similar to the "median" (thats  
>> the name of
>> the command) test already implemented in Stata, but unfortunately I  
>> cannot
>> program .ado files and I could not find a user-written procedure.
>> Any idea how to go about this?
>> P.S. the number of observations in the fifth percentile is pretty low
>> (around 6), so one might have to use something with bootstrap or
>> permutations.
>>
>> Thank you so much in advance
>> susanne
>>
>>
>>
>> *
>> *   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/
>>
>
>
>
> --
> To every ω-consistent recursive class κ of formulae there correspond
> recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
> belongs to Flg(κ) (where v is the free variable of r).
>
> *
> *   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/


*
*   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/


*
*   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/
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Re: st: test difference in quintiles

Tirthankar Chakravarty
In reply to this post by Susanne Neckermann
<>

I will assume your conditioning variables Y & Z are binary.

In the -auto- dataset, consider that you want to test the difference
in the 5th percentile of the variable "mpg" if price is greater than
$6000 (condition1, variable "pricedummy") or if the car is of foreign
origin (condition 2, variable "foreign"). Then the code below should
do what you want. Also, it might be a good idea to plot the kernel
density estimates when considering tail-behaviour of distributions.
Else if you only have one conditioning variable (case1, cond_var==1;
case 2, cond_var==0), then Martin's code is probably more useful.

/* More on bootstrapping percentiles */
sysuse auto, clear
g pricedummy=(price>6000)
tab pricedummy
cap prog drop pctile_bs
program define pctile_bs, rclass
        version 10
        syntax varlist(max=3 min=3) [if] [in]
        marksample touse
        tokenize `varlist'
        local first `1'
        macro shift
        local second `1'
        macro shift
        local third `1'
        _pctile `first' if (`touse' & `second'==1), percentiles(5)
        scalar pc1 = r(r1)
        _pctile `first' if (`touse' & `third'==1), percentiles(5)
        scalar pc2 = r(r1)
        return scalar dpc = pc1-pc2
        ereturn post, esample(`touse')
end
bootstrap  Dpc = r(dpc), reps(2000) dots: pctile_bs mpg foreign pricedummy
twoway (kdensity mpg if foreign==1) (kdensity mpg if pricedummy==1,
legend(order(1 "foreign" 2 "pricedummy")))
/* end */

Simply substitute your variables in the line as follows:
bootstrap  Dpc = r(dpc), reps(2000) dots: pctile_bs X Y Z

T

--- References ---
Statalist discussion:
http://www.stata.com/statalist/archive/2004-02/msg00618.html

On Wed, Jun 10, 2009 at 4:44 PM, Martin Weiss<[hidden email]> wrote:

>
> <>
>
> Try:
>
> *************
> clear*
> set obs 10000
> capt prog drop differ
>
> gen x= rnormal()
>
> /*no systematic difference btw
> groups
> THIS IS equivalent to your
> Y and Z conditions*/
> gen condition=runiform()<0.5
>
> pr differ, rclass
>        vers 10.1
>        qui su x if /*
>  */ condition==0,/*
>  */ det
>  loc first=r(p5)
>  qui su x if /*
>  */ condition==1,/*
>  */ det
>  ret sca diff = r(p5)-`first'
> end
>
> bs diff=r(diff), /*
>  */ reps(200): differ
>
> *************
>
>
>
> HTH
> Martin
>
>
> -----Ursprüngliche Nachricht-----
> Von: [hidden email] [mailto:[hidden email]] Im Auftrag von Susanne Neckermann
> Gesendet: Mittwoch, 10. Juni 2009 17:38
> An: [hidden email]
> Betreff: Re: st: test difference in quintiles
>
> Dear T
>
> thank you very much for the message!!
> I am a real beginner with Stata and I have to admit that I do not
> quite understand how to transfer the code to my case.
> I have a variable X that I observe under two conditions Y and Z. I
> want to see if the fifth percentile of variable X in condition Y is
> different from the fifth percentile of X in condition Z.
>
> Thank you so much for your input!!
> Best
> Susanne
>
> On 10-Jun-09, at 5:26 PM, Tirthankar Chakravarty wrote:
>
>> <>
>>
>> This is a variation of previous advice:
>> http://www.stata.com/statalist/archive/2009-05/msg00311.html
>>
>> I believe you want to test the significance of the difference of the
>> 5th percentile for two variables using a bootstrap. If this is the
>> case, then the code below applies:
>>
>> /* Bootstrap the difference of percentiles */
>> clear
>> webuse nlswork, clear
>> keep idcode year ttl_exp
>> reshape wide ttl_exp, i(idcode) j(year)
>>
>> cap prog drop pctile_bs
>> program define pctile_bs, rclass
>>       version 10
>>       syntax varlist(max=2 min=2) [if] [in]
>>       marksample touse
>>       tokenize `varlist'
>>       local first `1'
>>       macro shift
>>       local second `*'
>>       _pctile `first' if `touse', percentiles(5)
>>       scalar pc1 = r(r1)
>>       _pctile `second' if `touse', percentiles(5)
>>       scalar pc2 = r(r1)
>>       return scalar dpc = pc1-pc2
>>       ereturn post, esample(`touse')
>> end
>> bootstrap  Dpc = r(dpc), reps(2000) dots: pctile_bs ttl_exp68
>> ttl_exp69
>> /* End */
>>
>> Please also see the reference about pivotal statistics in a bootstrap
>> from the previous message.
>>
>> T
>>
>>
>> On Wed, Jun 10, 2009 at 3:57 PM, Susanne
>> Neckermann<[hidden email]> wrote:
>>> Hi!
>>>
>>> I want to test whether the difference in the fifth percentile of two
>>> distributions is significant.
>>> In principle, this test should be similar to the "median" (thats
>>> the name of
>>> the command) test already implemented in Stata, but unfortunately I
>>> cannot
>>> program .ado files and I could not find a user-written procedure.
>>> Any idea how to go about this?
>>> P.S. the number of observations in the fifth percentile is pretty low
>>> (around 6), so one might have to use something with bootstrap or
>>> permutations.
>>>
>>> Thank you so much in advance
>>> susanne
>>>
>>>
>>>
>>> *
>>> *   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/
>>>
>>
>>
>>
>> --
>> To every ω-consistent recursive class κ of formulae there correspond
>> recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
>> belongs to Flg(κ) (where v is the free variable of r).
>>
>> *
>> *   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/
>
>
> *
> *   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/
>
>
> *
> *   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/
>



--
To every ω-consistent recursive class κ of formulae there correspond
recursive class signs r, such that neither v Gen r nor Neg(v Gen r)
belongs to Flg(κ) (where v is the free variable of r).

*
*   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/
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Re: st: test difference in quintiles

Steven Samuels
This post was updated on .
In reply to this post by Susanne Neckermann
CONTENTS DELETED
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RE: st: test difference in quintiles

Roger Newson
Thanks to Samuel for the promotion. However, -cendif- computes confidence intervals, not for differences between percentiles, but for percentile differences. These are not exactly the same thing. For a counterexample, see Newson (2008).

If Suzanne wants confidence intervals for the differences between 2 5th percentiles for 2 subpopulations, then Suzanne should probably use the -centile- command to get confidence intervals for the 2 5th percentiles, and then use the -invcise- package and the -metaparm- module of the -parmest- package, downloadable from SSC, to get a confidence interval for the difference between the 2 5th percentiles. The -invcise- package calculates standard errors using the inverse confidence interval method.

I hope this helps.

Best wishes

Roger

References

Newson, R. B. Hodges-Lehmann median differences between exponential subpopulations. Downloadable from
http://www.imperial.ac.uk/nhli/r.newson/papers.htm#miscellaneous_documents
as from 12 October 2008.


Roger B Newson BSc MSc DPhil
Lecturer in Medical Statistics
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute
Imperial College London
Royal Brompton Campus
Room 33, Emmanuel Kaye Building
1B Manresa Road
London SW3 6LR
UNITED KINGDOM
Tel: +44 (0)20 7352 8121 ext 3381
Fax: +44 (0)20 7351 8322
Email: [hidden email]
Web page: http://www.imperial.ac.uk/nhli/r.newson/
Departmental Web page:
http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgenetics/reph/

Opinions expressed are those of the author, not of the institution.

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of [hidden email]
Sent: 10 June 2009 22:42
To: [hidden email]
Subject: Re: st: test difference in quintiles

-cendif-  by Roger Newson, is part of the -somersd- package,
downloadable from SSC (type "ssc install somersd".  It computes CI's
for,  and tests, differences between medians.  You will need  large
sample sizes to test the difference between 5th percentiles with
reasonable power.  What do you mean by "number of observations in the
5th percentile"?  You should not group data prior to the analysis.

-Steve



On Wed, Jun 10, 2009 at 10:57 AM, Susanne
Neckermann<[hidden email]> wrote:

> Hi!
>
> I want to test whether the difference in the fifth percentile of two
> distributions is significant.
> In principle, this test should be similar to the "median" (thats the name of
> the command) test already implemented in Stata, but unfortunately I cannot
> program .ado files and I could not find a user-written procedure.
> Any idea how to go about this?
> P.S. the number of observations in the fifth percentile is pretty low
> (around 6), so one might have to use something with bootstrap or
> permutations.
>
> Thank you so much in advance
> susanne
>
>
>
> *
> *   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/
>

*
*   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/

*
*   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/
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AW: st: test difference in quintiles

Martin Weiss-5

<>

Susanne asked me privately for further advice and also mentioned that she
could not figure out the implementation of Roger`s post. From what I
understand, the solution proposed by Roger should look like:


*************
clear*
set obs 10000
capt ssc inst invcise
capt ssc inst parmest

gen x= rnormal()

/*
no systematic
difference btw groups
*/

gen byte condition=/*
*/ runiform()<0.5

/*just to check
plausibility of results */
by con, sort : /*
*/ summarize x, detail

statsby N=r(N) p5=r(c_1) /*
*/ p5min=r(lb_1) p5max=r(ub_1),/*
*/  by(condition)/*
*/  clear: centile x, c(5)
 
invcise p5min p5max, /*
 */ stderr(icse)
 
metaparm [iweight=(cond==1)-(cond==0)],/*
 */ norestore sumvar(N)/*
 */ estimate(p5) stderr(icse)

list, noobs
*************



HTH
Martin

-----Ursprüngliche Nachricht-----
Von: [hidden email]
[mailto:[hidden email]] Im Auftrag von Newson, Roger B
Gesendet: Donnerstag, 11. Juni 2009 10:45
An: '[hidden email]'
Betreff: RE: st: test difference in quintiles

Thanks to Samuel for the promotion. However, -cendif- computes confidence
intervals, not for differences between percentiles, but for percentile
differences. These are not exactly the same thing. For a counterexample, see
Newson (2008).

If Suzanne wants confidence intervals for the differences between 2 5th
percentiles for 2 subpopulations, then Suzanne should probably use the
-centile- command to get confidence intervals for the 2 5th percentiles, and
then use the -invcise- package and the -metaparm- module of the -parmest-
package, downloadable from SSC, to get a confidence interval for the
difference between the 2 5th percentiles. The -invcise- package calculates
standard errors using the inverse confidence interval method.

I hope this helps.

Best wishes

Roger

References

Newson, R. B. Hodges-Lehmann median differences between exponential
subpopulations. Downloadable from
http://www.imperial.ac.uk/nhli/r.newson/papers.htm#miscellaneous_documents
as from 12 October 2008.


Roger B Newson BSc MSc DPhil
Lecturer in Medical Statistics
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute
Imperial College London
Royal Brompton Campus
Room 33, Emmanuel Kaye Building
1B Manresa Road
London SW3 6LR
UNITED KINGDOM
Tel: +44 (0)20 7352 8121 ext 3381
Fax: +44 (0)20 7351 8322
Email: [hidden email]
Web page: http://www.imperial.ac.uk/nhli/r.newson/
Departmental Web page:
http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgene
tics/reph/

Opinions expressed are those of the author, not of the institution.

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of
[hidden email]
Sent: 10 June 2009 22:42
To: [hidden email]
Subject: Re: st: test difference in quintiles

-cendif-  by Roger Newson, is part of the -somersd- package,
downloadable from SSC (type "ssc install somersd".  It computes CI's
for,  and tests, differences between medians.  You will need  large
sample sizes to test the difference between 5th percentiles with
reasonable power.  What do you mean by "number of observations in the
5th percentile"?  You should not group data prior to the analysis.

-Steve



On Wed, Jun 10, 2009 at 10:57 AM, Susanne
Neckermann<[hidden email]> wrote:
> Hi!
>
> I want to test whether the difference in the fifth percentile of two
> distributions is significant.
> In principle, this test should be similar to the "median" (thats the name
of

> the command) test already implemented in Stata, but unfortunately I cannot
> program .ado files and I could not find a user-written procedure.
> Any idea how to go about this?
> P.S. the number of observations in the fifth percentile is pretty low
> (around 6), so one might have to use something with bootstrap or
> permutations.
>
> Thank you so much in advance
> susanne
>
>
>
> *
> *   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/
>

*
*   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/

*
*   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/


*
*   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/
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RE: st: test difference in quintiles

Roger Newson
Thanks to Martin for helpfully spelling out what Suzanne needed to do. This was essentially what I had in mind.

Best wishes

Roger


Roger B Newson BSc MSc DPhil
Lecturer in Medical Statistics
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute
Imperial College London
Royal Brompton Campus
Room 33, Emmanuel Kaye Building
1B Manresa Road
London SW3 6LR
UNITED KINGDOM
Tel: +44 (0)20 7352 8121 ext 3381
Fax: +44 (0)20 7351 8322
Email: [hidden email]
Web page: http://www.imperial.ac.uk/nhli/r.newson/
Departmental Web page:
http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgenetics/reph/

Opinions expressed are those of the author, not of the institution.

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Martin Weiss
Sent: 11 June 2009 15:59
To: [hidden email]
Subject: AW: st: test difference in quintiles


<>

Susanne asked me privately for further advice and also mentioned that she
could not figure out the implementation of Roger`s post. From what I
understand, the solution proposed by Roger should look like:


*************
clear*
set obs 10000
capt ssc inst invcise
capt ssc inst parmest

gen x= rnormal()

/*
no systematic
difference btw groups
*/

gen byte condition=/*
*/ runiform()<0.5

/*just to check
plausibility of results */
by con, sort : /*
*/ summarize x, detail

statsby N=r(N) p5=r(c_1) /*
*/ p5min=r(lb_1) p5max=r(ub_1),/*
*/  by(condition)/*
*/  clear: centile x, c(5)
 
invcise p5min p5max, /*
 */ stderr(icse)
 
metaparm [iweight=(cond==1)-(cond==0)],/*
 */ norestore sumvar(N)/*
 */ estimate(p5) stderr(icse)

list, noobs
*************



HTH
Martin

-----Ursprüngliche Nachricht-----
Von: [hidden email]
[mailto:[hidden email]] Im Auftrag von Newson, Roger B
Gesendet: Donnerstag, 11. Juni 2009 10:45
An: '[hidden email]'
Betreff: RE: st: test difference in quintiles

Thanks to Samuel for the promotion. However, -cendif- computes confidence
intervals, not for differences between percentiles, but for percentile
differences. These are not exactly the same thing. For a counterexample, see
Newson (2008).

If Suzanne wants confidence intervals for the differences between 2 5th
percentiles for 2 subpopulations, then Suzanne should probably use the
-centile- command to get confidence intervals for the 2 5th percentiles, and
then use the -invcise- package and the -metaparm- module of the -parmest-
package, downloadable from SSC, to get a confidence interval for the
difference between the 2 5th percentiles. The -invcise- package calculates
standard errors using the inverse confidence interval method.

I hope this helps.

Best wishes

Roger

References

Newson, R. B. Hodges-Lehmann median differences between exponential
subpopulations. Downloadable from
http://www.imperial.ac.uk/nhli/r.newson/papers.htm#miscellaneous_documents
as from 12 October 2008.


Roger B Newson BSc MSc DPhil
Lecturer in Medical Statistics
Respiratory Epidemiology and Public Health Group
National Heart and Lung Institute
Imperial College London
Royal Brompton Campus
Room 33, Emmanuel Kaye Building
1B Manresa Road
London SW3 6LR
UNITED KINGDOM
Tel: +44 (0)20 7352 8121 ext 3381
Fax: +44 (0)20 7351 8322
Email: [hidden email]
Web page: http://www.imperial.ac.uk/nhli/r.newson/
Departmental Web page:
http://www1.imperial.ac.uk/medicine/about/divisions/nhli/respiration/popgene
tics/reph/

Opinions expressed are those of the author, not of the institution.

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of
[hidden email]
Sent: 10 June 2009 22:42
To: [hidden email]
Subject: Re: st: test difference in quintiles

-cendif-  by Roger Newson, is part of the -somersd- package,
downloadable from SSC (type "ssc install somersd".  It computes CI's
for,  and tests, differences between medians.  You will need  large
sample sizes to test the difference between 5th percentiles with
reasonable power.  What do you mean by "number of observations in the
5th percentile"?  You should not group data prior to the analysis.

-Steve



On Wed, Jun 10, 2009 at 10:57 AM, Susanne
Neckermann<[hidden email]> wrote:
> Hi!
>
> I want to test whether the difference in the fifth percentile of two
> distributions is significant.
> In principle, this test should be similar to the "median" (thats the name
of

> the command) test already implemented in Stata, but unfortunately I cannot
> program .ado files and I could not find a user-written procedure.
> Any idea how to go about this?
> P.S. the number of observations in the fifth percentile is pretty low
> (around 6), so one might have to use something with bootstrap or
> permutations.
>
> Thank you so much in advance
> susanne
>
>
>
> *
> *   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/
>

*
*   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/

*
*   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/


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