Re: st: Using sampling/probability weights for mixed design ANOVA in STATA

[Steven Samuels <sjsamuels@gmail.com>]

Hi, Meg.

Welcome to Stata!  You will find that Stata's regression and survey capabilities are both far superior to those of SPSS. 

 But The description of your data  unclear.  You refer to one between-subject and two within-subject "variables", but to "the" (single?) repeated measures variable with two levels. Isn't this a within-subject variable?.  By two levels do you mean two occasions (if longitudinal)?  Which, if any variables (besides subject), do you consider to be "random effects"?

So please clarify what the variables are and  list the data for some  subjects, so that we can see where you are starting from,. 

In any case, for complex survey data, the standard errors for estimates are governed by variation of primary sampling units (PSUs, first-stage clusters) within strata, so the usual ANOVA formulas would not ordinarily apply. Stata can analyze some mixed model designs with survey data.

Some other questions that will help us suggest analyses:
1. What is the sampling design? If there were strata, do they correspond to the "between-subject" variable?
2. Are replicate (bootstrap, jackknife, BRR) weights available? Did the survey distributor provide SAS or SPSS macros to compute them? 
3. What questions are you trying to answer.  What parameters do you hope to estimate or test in your analysis?
4. What version of Stata do you have>

Steve
sjsamuels@gmail.com
	
	
On May 23, 2011, at 9:20 AM, Meg Dennison wrote:

Hi,

I have a complex sample, for which I need to use sampling weights
(probability weights). I already have these values derived from the
initial sampling selection. I wanted to then perform a mixed design
ANOVA (with 2 within subjects variables and one between subjects
variable).The repeated measures variable only has 2 levels.

I have only used SPSS before and the Complex Sampling Add-on module
only allows for univariate ANOVA. Can STATA perform this type of
analysis? From what I could see from looking at the GUI and reading
the manual, probability weights (pweights) could not be used for mixed
ANOVA?

Is there another way I should be thinking about this?

Thanks in advance for your help,


Kind regards,

Meg

-- 

Meg Dennison BA(Hons) MPsych(Clin)/PhD Candidate
School of Psychological Sciences, University of Melbourne
megd@student.unimelb.edu.au
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