Re: st: mean and SD by categories

[Federico Belotti <f.belotti@gmail.com>]

Did you update -estout- from SSC?

ssc install estout, replace



On Jul 16, 2013, at 5:01 PM, Dherani, Mukesh wrote:

> Thank you Nick and Federico. This code runs fine but ends up on one error message:
> 
> . estimation result m(all) not found
> 
> While I digest the code can you please let me know why?
> 
> BW,m
> 
> 
> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of Federico Belotti
> Sent: 16 July 2013 14:09
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: mean and SD by categories
> 
> Ops. Sorry... I wrote the code too quickly
> 
> qui {
> local lab
> cap mat drop all mean sd up lo
> forval a=1/2 {
> 	forval b=1/7 {
> 		forval c=1/5  { 
> 			sum bmi if sex==`a' & agegp==`b' & ses==`c'
> 			mat mean = nullmat(mean) \ r(mean)
> 			mat sd = nullmat(sd) \ r(sd)
> 			mat up = nullmat(up) \ r(mean)+(1.96*r(sd)/sqrt(r(N)))
> 			mat lo = nullmat(lo) \ r(mean)-(1.96*r(sd)/sqrt(r(N)))
> 			local lab `"`lab' "sex=`a' agegp=`b' ses=`c'""'
> 		}
> 	}
> }
> mat all = (mean,sd,lo,up)
> mat rown all = `lab'
> mat coln all = mean sd lb ub
> noi estout m(all), varw(22) mlab(,none) }
> 
> 
> 
> On Jul 16, 2013, at 3:02 PM, Nick Cox wrote:
> 
>> You need to take square roots of the sample sizes in calculating 
>> standard errors.
>> Nick
>> njcoxstata@gmail.com
>> 
>> 
>> On 16 July 2013 13:56, Federico Belotti <f.belotti@gmail.com> wrote:
>>> This could be a strategy to get a table using Ben Jann -estout- 
>>> command
>>> 
>>> qui {
>>> forval a=1/2 {
>>>       forval b=1/7 {
>>>               forval c=1/5  {
>>>                       sum bmi if sex==`a' & agegp==`b' & ses==`c'
>>>                       mat mean = nullmat(mean) \ r(mean)
>>>                       mat sd = nullmat(sd) \ r(sd)
>>>                       mat up = nullmat(up) \ r(mean)+(1.96*r(sd)/r(N))
>>>                       mat lo = nullmat(lo) \ r(mean)-(1.96*r(sd)/r(N))
>>>                       local lab `"`lab' "sex=`a' agegp=`b' ses=`c'""'
>>>               }
>>>       }
>>> }
>>> mat all = (mean,sd,lo,up)
>>> mat rown all = `lab'
>>> mat coln all = mean sd lb ub
>>> noi estout m(all), varw(22) mlab(,none) }
>>> 
>>> Federico
>>> 
>>> On Jul 16, 2013, at 2:23 PM, Nick Cox wrote:
>>> 
>>>> There are various problems with your approach.
>>>> 
>>>> 1. The immediate problem is that you cycle over combinations of 
>>>> categories creating local macros with names like mean111, sd111, and 
>>>> so forth.
>>>> 
>>>> But a command like
>>>> 
>>>> display mean111
>>>> 
>>>> is understood by Stata to mean that you want to see a value of a 
>>>> variable -mean111- or a scalar -mean111-, but you have no such 
>>>> variable or scalar, hence the message you received.
>>>> 
>>>> To see the value of a local macro, you would need to do something 
>>>> like
>>>> 
>>>> display `mean111'
>>>> 
>>>> 2. Adding +/- 1.96 SD to the mean is an attempt to get 95% 
>>>> confidence intervals. But there are at least two problems here. 1.96 
>>>> is an optimistic multiplier and a more accurate multiplier would be 
>>>> based on the t-distribution. However, that's secondary compared with 
>>>> using SDs when you should be using standard errors.
>>>> 
>>>> 3. A strategic difficulty here is that creating lots of local macros 
>>>> first is not a good way to create graphs. In fact if you are a 
>>>> novice in programming trying to program graphs from scratch is not advisable.
>>>> In your case 70 cross-combinations seems likely to produce only a 
>>>> very complicated graph. Much depends on whether each 
>>>> cross-combination is well enough represented to show stable patterns.
>>>> 
>>>> -stripplot- from SSC may be of help. It has a -ci- option that means 
>>>> that confidence intervals are shown for you.
>>>> 
>>>> Nick
>>>> njcoxstata@gmail.com
>>>> 
>>>> 
>>>> On 16 July 2013 12:43, Dherani, Mukesh <M.K.Dherani@liverpool.ac.uk> wrote:
>>>>> Dear all,
>>>>> I am very novice in programming.
>>>>> I have a dataset with BMI by three categorical variables age (7 groups), sex (2 groups) and SES (5 groups).  I was to generate a line graph showing mean BMI with 95%CI by age , sex  and SES.  Below is my code to create local that I want to use in twoway line graph:
>>>>> 
>>>>> forval a=1/2 {
>>>>> forval b=1/7 {
>>>>> forval c=1/5  {
>>>>> sum bmi if sex==`a' & agegp==`b' & ses==`c'
>>>>> local mean`a'`b'`c'=r(mean)
>>>>> local sd`a'`b'`c'=r(sd)
>>>>> local up`a'`b'`c'=r(mean)+(1.96*r(sd)) local 
>>>>> lo`a'`b'`c'=r(mean)-(1.96*r(sd)) di mean`a'`b'`c' sd`a'`b'`c' 
>>>>> up`a'`b'`c' lo`a'`b'`c'
>>>>> }
>>>>> }
>>>>> }
>>>>> 
>>>>> 
>>>>> At the end of this command stata says mean111 was not found!
>>>>> Secondly, I want graph to show me mean bmi (y axis) and age (x axis) for each ses for each sex separately. Should I carry this out in the loop or outside the loop?
>>>>> 
>>>>> Any help is highly appreciated.
>>>>> 
>>>>> BW,m
>>>>> 
>>>>> 
>>>>> *
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>>>> 
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>>> 
>>> --
>>> Federico Belotti, PhD
>>> Research Fellow
>>> Centre for Economics and International Studies University of Rome Tor 
>>> Vergata
>>> tel/fax: +39 06 7259 5627
>>> e-mail: federico.belotti@uniroma2.it
>>> web: http://www.econometrics.it
>>> 
>>> 
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>> 
>> *
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> 
> --
> Federico Belotti, PhD
> Research Fellow
> Centre for Economics and International Studies University of Rome Tor Vergata
> tel/fax: +39 06 7259 5627
> e-mail: federico.belotti@uniroma2.it
> web: http://www.econometrics.it
> 
> 
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> 
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-- 
Federico Belotti, PhD
Research Fellow
Centre for Economics and International Studies
University of Rome Tor Vergata
tel/fax: +39 06 7259 5627
e-mail: federico.belotti@uniroma2.it
web: http://www.econometrics.it


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