try resetting your levels? if that doesn't work, please dput() an example
data set that we can test with :) thanks!
sii.design <- update( sii.design , d6 = factor( d6 ) )
On Wed, Nov 12, 2014 at 7:59 AM, Martin Canon <martin.canon at gmail.com>
wrote:
> Hi.
>
>
> I'm trying to calculate the weighted mean score of a quality of life
> measure (ovt) in patients with irritable bowel syndrome by their
> marital status (d7).
>
> This is a summary of the structure of the dataset:
>
> > str(sii.tesis)
> 'data.frame': 1063 obs. of 75 variables:
> $ id : int 51 52 53 54 55 56 57 58 59 60 ...
> $ stratum : Factor w/ 6 levels "MEst","MAcad",..: 1
4 NA 4 4 1 6 NA 4
> 4 ...
> $ expfc : num 22.8 17.1 NA 17.1 17.1 ...
> $ d6 : Factor w/ 3 levels
"Estudiante","Profesor",..: 1 1 NA
> 1 1 1 3 NA 1 1 ...
> $ d7 : Factor w/ 6 levels
"Soltero","Casado",..: 1 1 NA 1 1 1
> 1 NA 1 1 ...
> $ d7c : Factor w/ 2 levels "No
estable","Estable": 1 1 NA 1 1
> 1 1 NA 1 1 ...
> $ s1cm : Factor w/ 2 levels "No","Si": 1 2 NA 1
1 1 2 NA 1 1 ...
> $ ovt : num NA 93.4 NA NA NA ...
>
> I declared the sampling design:
>
> > sii.design <- svydesign(
> id = ~1,
> strata = ~stratum,
> weights = ~expfc,
> data = subset(sii.tesis, !is.na(stratum)))
>
> Then I tried to get the result:
>
> > svyby(~ovt, ~d7, sii.design, svymean, na.rm = TRUE, level = 0.95)
>
> but i get the error:
>
> Error in tapply(1:NROW(x), list(factor(strata)), function(index) { :
> arguments must have same length
>
>
> The length of both variables is the same. If the variable ovt exists,
> there is a d7 match in the data frame.
>
> I try the same thing using another variable instead - "role" (d6)
-
> and it works.
>
> > svyby(~ovt, ~d6, sii.design, svymean, na.rm = TRUE, level = 0.95)
> d6 ovt se
> Estudiante Estudiante 71.01805 1.370569
> Profesor Profesor 72.30923 6.518378
> Administrativo Administrativo 75.69102 3.715050
>
> If I use the recategorized d7 variable (d7c, two levels only) it works
> too:
>
> > svyby(~ovt, ~d7c, sii.design, svymean, na.rm = TRUE, level = 0.95)
> d7c ovt se
> No estable No estable 70.92344 1.37460
> Estable Estable 74.53719 4.16954
>
>
> What could be the problem?
>
>
> Regards.
>
>
> Martin Canon
> Colombia, South America
>
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