Re: [R] Weighted box or violin plots in Lattice?

From: David Winsemius <dwinsemius_at_comcast.net>
Date: Mon, 09 May 2011 08:12:18 -0400

On May 9, 2011, at 12:35 AM, Deepayan Sarkar wrote:

```>> On Mon, May 9, 2011 at 6:35 AM, Deepayan Sarkar
>> <deepayan.sarkar_at_gmail.com> wrote:
>>> On Sat, May 7, 2011 at 1:55 AM, Raphael Mazor
>>> <raphaelm_at_sccwrp.org> wrote:
>>>> Is it possible to create weighted boxplots or violin plots in
>>>> lattice?
>>>>
>>>> It seems that you can specify weights for panel.histogram() and
>>>> panel.densityplot(), but not for panel.bwplot or panel.violin().
>>>
>>> Not for panel.histogram() either.
>>>
>>> It's not immediately obvious how you would get weighted boxplots.
>>
>> The way the survey world does it is to get weighted quantiles and
>> work
>> from them, as in survey:::svyboxplot().  The only tricky decision is
>> what to do with outliers, since I haven't been able to think of any
>> good way of indicating weights on them.
>
```

> So I guess with bwplot() one would have to write a version of
> boxplot.stats() that uses weighted quantiles, and then write a
> modified panel function.
```>
```

> A crude approximation (if the weights don't vary too much) may be to
> scale and round the weights to integers, and then repeat each data
> point; e.g., newx <- rep(x, w), etc.

You could do a bit better if you just substituted wtd.quantile from Hmisc with an x and weights argument for the fivenum call in boxplot.stats.

require(Hmisc)
> ?wtd.quantile
> fivenum(x=1:10)
[1] 1.0 3.0 5.5 8.0 10.0
> wtd.quantile(x=1:10)

0% 25% 50% 75% 100%
1.00 3.25 5.50 7.75 10.00
> wtd.quantile( x = 1:10, weights = 1:10)    0% 25% 50% 75% 100%
1 5 7 9 10

(Most people think the hinges are at the 25th and 75th percentiles anyway.)

```>
```

> -Deepayan
```>

> ______________________________________________
```
> R-help_at_r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> and provide commented, minimal, self-contained, reproducible code.

David Winsemius, MD
West Hartford, CT

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Mon 09 May 2011 - 12:20:10 GMT

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