[R] I don't understand the result of `svyboxplot` function from the Survey package

[Anthony Damico]

hi, nice catch!  i'm ccing the author of the survey package because this
might be a issue.  when i run ?svyboxplot, i also see all three boxes in
the exact same place..  seems like the svyby() call inside of svyboxplot
does something unexpected when svyquantile gets passed using keep.var=FALSE
and ci=FALSE


library(survey)

data(api)

dstrat <- svydesign(id = ~1, strata = ~stype, weights = ~pw, data =
apistrat, fpc = ~fpc)

# looks OK
svyby(~enroll, ~stype, dstrat, svyquantile, quantiles = c(0, 0.25, 0.5,
0.75, 1), na.rm = TRUE)

# returns each result three times in an unexpected configuration..
svyboxplot then grabs the repeated information from the first six columns
svyby(~enroll, ~stype, dstrat, svyquantile, ci = FALSE, keep.var = FALSE,
quantiles = c(0, 0.25, 0.5, 0.75, 1), na.rm = TRUE)





On Tue, Aug 2, 2022 at 7:30 AM Iulia Dumitru <iuliadmtru using gmail.com> wrote:

> After following the example given here:
> https://www.rdocumentation.org/packages/survey/versions/4.1-1/topics/svyhist
> for `svyboxplot` I get the result in the attached image. This is a box
> plot of the `enroll` variable from the stratified dataset `apistrat`,
> grouped by `stype`: E (elementary school), M (middle school) and H (high
> school). If I use the `svyby` function to group the data by `stype` and
> find the mean for each group, I get this result:
>
> > svyby(~enroll, ~stype, dstrat, svymean)
>   stype  enroll       se
> E     E  416.78 16.41740
> H     H 1320.70 91.70781
> M     M  832.48 54.52157
>
> Clearly the means are very different from each other. Then why don’t the
> box plots show this? I don’t know how to interpret the plot. Could someone
> please offer some insight on this? Thank you!
>
>
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