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Re: st: multiple CI/mean plots in one graphic


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: multiple CI/mean plots in one graphic
Date   Fri, 29 Apr 2011 09:42:34 +0100

The commands are (on separate lines)

sysuse auto, clear

statsby mean=r(mean) ub=r(ub) lb=r(lb) , by(foreign rep78) : ci weight

separate mean, by(foreign) veryshortlabel

separate ub, by(foreign) veryshortlabel

separate lb, by(foreign) veryshortlabel

scatter mean0 mean1 rep78 || rcap ub0 lb0 rep78 || rcap ub1 lb1 rep78,
legend(order(1 2))

Note that the command -separate- is spelled in that way, but Stata
does for once indulge the spelling -seperate- when used for the
command. See
http://www.stata.com/statalist/archive/2008-11/msg00939.html
for the story.

On Fri, Apr 29, 2011 at 8:17 AM, Pieter-Jan <duikerarts@home.nl> wrote:
> Dear Nick,
>
> Thanks for your reply. I tried to dally around with the auto database and
> use the commands your wrote down
>
> Sysuse auto, clear
> statsby mean=r(mean) ub=r(ub) lb=r(lb), by(foreign rep78): ci weight
> seperate mean, by(foreign) veryshortlabel seperate ub, by(foreign)
> veryshortlabel seperate lb, by(foreign) veryshortlabel scatter mean0 mean1
> rep78 || rcap ub0 lb0 rep78 || rcap ub1 lb1 rep78, legend(order(1 2))
>
> This gave me the error message
> invalid 'by'
> r(198);
>
> As I use the individual commands
> statsby mean=r(mean) ub=r(ub) lb=r(lb), by(foreign rep78): ci weight
> seperate mean
> (running ci on estimation sample)
> variable seperate not found
> an error occurred when statsby executed ci
> r(111);
>
> Tried to axecute without the separate mean commands
> statsby mean=r(mean) ub=r(ub) lb=r(lb), by(foreign rep78): ci weight
> (running ci on estimation sample)
>
>      command:  ci weight
>         mean:  r(mean)
>           ub:  r(ub)
>           lb:  r(lb)
>           by:  foreign rep78
>
> Statsby groups
> ----+--- 1 ---+--- 2 ---+--- 3 ---+--- 4 ---+--- 5
> ........
>
> . by(foreign) veryshortlabel seperate ub
> : required
> r(100);
>
> I think I did something wrong regarding the commands but can not figure out
> what. Is there a simple solution?
> Thanks
>
> Pieter-Jan van Ooij
>
>
> -----Oorspronkelijk bericht-----
> Van: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] Namens Nick Cox
> Verzonden: 28 april 2011 21:40
> Aan: statalist@hsphsun2.harvard.edu
> Onderwerp: Re: st: multiple CI/mean plots in one graphic
>
> -civplot- is a user-written plot from SSC written in 1999 for Stata 6.
> I am not surprised that it does not separate out different groups
> given a command
>
> . civplot variable1, by(time)
>
> as the command does not even mention -group-. Also, as -njc_stuff-
> (also SSC) documents, -civplot- is considered obsolete given -ciplot-
> (also SSC).
>
> But better than either is to do it yourself using the principles described
> in
>
> Cox, N.J. 2010. Speaking Stata: The statsby strategy. Stata Journal
> 10, 143-151.
> http://www.stata-journal.com/article.html?article=gr0045
>
> The following problem has essentially similar structure to yours and
> shows some technique
>
> sysuse auto, clear
> statsby mean=r(mean) ub=r(ub) lb=r(lb) , by(foreign rep78) : ci weight
> separate mean, by(foreign) veryshortlabel
> separate ub, by(foreign) veryshortlabel
> separate lb, by(foreign) veryshortlabel
> scatter mean0 mean1 rep78 || rcap ub0 lb0 rep78 || rcap ub1 lb1 rep78,
> legend(order(1 2))
>
> However, note that what you have done so far implies that separate
> days are independent, which may not be quite right!
>
> Nick
>
> On Thu, Apr 28, 2011 at 6:33 PM, Pieter-Jan <duikerarts@home.nl> wrote:
>
>> Recently we performed a randomized crossover study in which we monitored
> the
>> lung function of a group of volunteers  during three days. Day 1 was used
> to
>> determine baseline lung function whereas day 2 and 3 were used to monitor
>> lung function after inhaling either placebo (air) or active gas (oxygen)
>> under hyperbaric  condition. During each measurement day lung function was
>> measured 6 times. All variables and observations were put in a dataset
> which
>> initially had the following format:
>>
>> ID           Group                  Time                     Variable1 etc
>> 1             0                      0                             6.19
>> 2             0                      0                             5.97
>> Etc
>>
>> ID exist of 13 persons
>> Group: 0 (baseline), 1 (placebo), 2 (active)
>> Time: 0, 2, 4, 8, 12, 22 hours after exposure
>>
>> To give the reader a good overview how f.e. variable 1 changes over time
>> within the 3 groups I want to plot the CI and mean of each group on each
>> time point in one graphic. I tried civplot
>>
>> Civplot variable1, by(time)
>>
>> But that gives me no separate plots of the three groups.
>>
>> I tried to change the dataset by deleting the group variable and changing
>> the Variable1 etc as follows
>>
>> ID           Time      Variable1_baseline        Variable1_placebo
>> Variable1_active etc
>> 1             0             6.19                     6.01
>> 6.11
>> 2             0             5.97                     6.05
>> 5.91
>>
>> Civplot variable1_baseline, by(time)
>>
>> This allows me only 1 civplot for each variable but just like the first
>> attempt this gave me only 1 plot per graphic. I tried also twoway
>>
>> Twoway (scatter variable1_baseline time) (fpfit variable1_baseline time)
>> (scatter variable1_placebo time) (fpfit variable1_placebo time) (scatter
>> variable1_active time) (fpfit variable1_active time)
>>
>> And this gives the possibilities of putting multiple plots in one graphic
>> but specially the scatter makes it cluttered. A simple CI/mean would
>> counteract this.
>>
>> Is there a possibility in Stata of putting multiple CI/mean plots into one
>> graphic? Maybe the answer speaks for itself but I am rather new into Stata
>> that's why I asking this question.

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