Statalist


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Repeated measures


From   Nikolaos Pandis <npandis@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Repeated measures
Date   Sat, 14 Mar 2009 12:21:49 -0700 (PDT)

Dear all,
 
Thank you for your responses. 
I apologize for the confusion on my data setup.
I am posting my exact data setup ( I hope it shows ok on the sent email):
 
WireType	wireno	trial	IntrusionForce (N)
A	1	1	1.42016
A	1	2	1.47212
A	1	3	1.44614
A	1	4	1.43748
A	1	5	1.52407
A	2	1	1.50675
A	2	2	1.44614
A	2	3	1.43748
A	2	4	1.4115
A	2	5	1.43748
A	3	1	1.42016
A	3	2	1.38552
A	3	3	1.47212
A	3	4	1.40284
A	3	5	1.40284
A	4	1	1.49809
A	4	2	1.42016
A	4	3	1.24697
A	4	4	1.34222
A	4	5	1.31625
A	5	1	1.42882
A	5	2	1.54139
A	5	3	1.42882
A	5	4	1.43748
A	5	5	1.54139
B	1	1	1.26429
B	1	2	1.17769
B	1	3	1.35088
B	1	4	1.3249
B	1	5	1.29893
B	2	1	1.1344
B	2	2	1.14306
B	2	3	1.52407
B	2	4	1.42882
B	2	5	1.43748
B	3	1	1.29893
B	3	2	1.24697
B	3	3	1.22965
B	3	4	1.30759
B	3	5	1.29027
B	4	1	1.29027
B	4	2	1.16037
B	4	3	1.16037
B	4	4	1.35088
B	4	5	1.35088
B	5	1	1.43748
B	5	2	1.39418
B	5	3	1.46346
B	5	4	1.54139
B	5	5	1.54139
C	1	1	9.5168
C	1	2	9.24835
C	1	3	9.31763
C	1	4	9.27433
C	1	5	9.24835
C	2	1	9.25701
C	2	2	9.30897
C	2	3	9.4735
C	2	4	9.22238
C	2	5	9.24835
C	3	1	9.11846
C	3	2	9.07516
C	3	3	9.16176
C	3	4	9.07516
C	3	5	9.12712
C	4	1	9.5601
C	4	2	9.71597
C	4	3	9.84586
C	4	4	9.67267
C	4	5	9.17908
C	5	1	9.23104
C	5	2	9.17908
C	5	3	9.22238
C	5	4	9.17908
C	5	5	9.21372
D	1	1	1.02182
D	1	2	0.94389
D	1	3	1.01316
D	1	4	1.0045
D	1	5	0.96121
D	2	1	0.83997
D	2	2	0.83131
D	2	3	1.01316
D	2	4	1.08244
D	2	5	1.08244
D	3	1	0.83997
D	3	2	0.85812
D	3	3	0.9274
D	3	4	0.89276
D	3	5	0.78802
D	4	1	1.10284
D	4	2	1.02099
D	4	3	1.16903
D	4	4	1.16037
D	4	5	1.06512
D	5	1	1.0478
D	5	2	1.02182
D	5	3	0.95255
D	5	4	1.1344
D	5	5	0.98718

Thank you very much for your help.
Best wishes,

Nikolaos


--- On Sat, 3/14/09, David Airey <david.airey@vanderbilt.edu> wrote:


From: David Airey <david.airey@vanderbilt.edu>
Subject: Re: st: Repeated measures
To: statalist@hsphsun2.harvard.edu
Date: Saturday, March 14, 2009, 6:33 PM


.

I think measurements nested in wire is the residual in the model

anova force wiretype / wireno|wiretype /

-Dave


On Mar 14, 2009, at 11:26 AM, TA Stat wrote:

> I think it is measurements nested in specimen nested in wiretype.
> Your main objective is to identify whether variation among wiretype is
> significant or not.  Right?
>
> Pete
>
> On Sat, Mar 14, 2009 at 11:12 PM, David Airey
> <david.airey@vanderbilt.edu> wrote:
>> .
>>
>> I was confused by your data layout.
>>
>> Your data are really just 3 columns wide:
>>
>> WireType WireNo Force
>>
>> where wiretype and wireno are replicated 5 times,
>>
>> So
>>
>> anova force wiretype / wireno|wiretype /
>>
>> is fine, or the equivalent xtmixed...
>>
>> -Dave
>>
>> On Mar 14, 2009, at 3:16 AM, Nikolaos Pandis wrote:
>>
>>> Dear Statalisters,
>>>
>>> I have the following dataset (except I have it in long format-one
>>> measurement per row) :
>>>
>>> WireType        WireNo  Trial           Force
>>>
>>> A       A1      1,2,3,4,5             5 measurements-1 per trial
>>> A       A2      1,2,3,4,5             5 measurements-1 per trial
>>> A       A3      1,2,3,4,5             5 measurements-1 per trial
>>> A       A4      1,2,3,4,5             5 measurements-1 per trial
>>> A       A5      1,2,3,4,5             5 measurements-1 per trial
>>>
>>> B       B1      1,2,3,4,5             5 measurements-1 per trial
>>> B       B2      1,2,3,4,5             5 measurements-1 per trial
>>> B       B3      1,2,3,4,5             5 measurements-1 per trial
>>> B       B4      1,2,3,4,5             5 measurements-1 per trial
>>> B       B5      1,2,3,4,5             5 measurements-1 per trial
>>>
>>>
>>> C       C1      1,2,3,4,5             5 measurements-1 per trial
>>> C       C2      1,2,3,4,5             5 measurements-1 per trial
>>> C       C3      1,2,3,4,5             5 measurements-1 per trial
>>> C       C4      1,2,3,4,5             5 measurements-1 per trial
>>> C       C5      1,2,3,4,5             5 measurements-1 per trial
>>>
>>> D       D1      1,2,3,4,5             5 measurements-1 per trial
>>> D       D2      1,2,3,4,5             5 measurements-1 per trial
>>> D       D3      1,2,3,4,5             5 measurements-1 per trial
>>> D       D4      1,2,3,4,5             5 measurements-1 per trial
>>> D       D5      1,2,3,4,5             5 measurements-1 per trial
>>>
>>> I am testing the forces generated by 4 different wiretypes to see  
>>> if there
>>> are significant differences.
>>> For each wiretype (categorical A B C D) I am using 5 specimens
>>> (A1-5,..D1-5) and for each specimen I am repeating the measurement  
>>> 5 times.
>>> The outcome is force and it is a continuous variable.
>>>
>>> This looks like a repeated measures with each trial nested in the  
>>> WireNo
>>> and the WireNo nested inside WireType?
>>>
>>> I was trying to use the xtgee command but I was not sure how to  
>>> construct
>>> it:
>>> xi:xtreg force i.xxxxx i.yyyyyy, i(zzzzz) ?
>>>
>>> Any help would be appreciated.
>>>
>>> Thank you very much,
>>>
>>> Nikolaos
>>>
>>>
>>>
>>>
>>> *
>>> *   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/



      

*
*   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/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index