[R] R Commander QQ Plot with triangular distribution

[Richard and Barbara Males]

Thank you for your prompt reply, I apologize for posting as an R
Commander question.  Your response is pointing me in the right
direction, but I am still not quite there.   The triangle package has
a qtriangle and dtriangle.   The formal arguments are a, b, and c.
(formals(qtriangle))  When I use R Commander as:

qqPlot(Transfer5000$Transfer.Rate, dist="triangle", a=3000,b=5000,c=4000)

I get the error message:

Error in qqPlot.default(Transfer5000$Transfer.Rate, dist = "triangle",  :
  argument 5 matches multiple formal arguments

and I am unclear as to how to specify that the "c" argument needs to
pertain specifically to the qtriangle (or perhaps dtriangle) function
arguments, that is, how to avoid a conflict with other arguments of
qqPlot that are ambiguous when passed "c"..

Again, sorry to post here, as this has clearly wandered into other
territory.  My exploratory searches to resolve this take me well
beyond my current ability in R.  If there is not an obvious answer, I
will re-post specifically on the topic of specifying formal arguments
of distributions to qqPlot.

Thanks.

Dick Males

On Tue, Mar 8, 2011 at 11:19 AM, John Fox <jfox at mcmaster.ca> wrote:
> Dear R. Males,
>
> This isn't really an R Commander question, since the qqPlot() function is in
> the car package and is just invoked by the R Commander.
>
> From ?qqPlot: "distribution: root name of comparison distribution - e.g.,
> "norm" for the normal distribution ... Any distribution for which quantile
> and density functions exist in R (with prefixes q and d, respectively) may
> be used." Thus, if there's a qtriangle() and dtriangle(), I suppose that you
> should be able to get a QQ plot. Further from ?qqPlot: " ...    arguments
> such as df to be passed to the appropriate quantile function." Thus, you
> should *name* the arguments to be passed to qtriangle() -- perhaps (of
> course, you should use the correct names) min=3000, max=5000, mode=4000.
>
> I hope this helps,
>  John
>
> --------------------------------
> John Fox
> Senator William McMaster
>  Professor of Social Statistics
> Department of Sociology
> McMaster University
> Hamilton, Ontario, Canada
> http://socserv.mcmaster.ca/jfox
>
>
>
>
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
>> On Behalf Of Richard and Barbara Males
>> Sent: March-08-11 10:49 AM
>> To: r-help at r-project.org
>> Subject: [R] R Commander QQ Plot with triangular distribution
>>
>> I am attempting to use the R Commander Graphs Quantile-Comparison
>> functionality on a dataset, to compare with a triangular distribution.
>>   I have the package triangle.   My question is on the syntax of how
>> to specify the parameters of the theoretical distribution in the
>> Parameters field of the dialog box.  For example, the theoretical
>> distribution has min of 3000, max of 5000, mode of 4000.   When I
>> enter this info as 3000,5000,4000 in the parameters field, I get:
>>
>> qqPlot(EmpiricalData$Value, dist="triangle", 3000,5000,4000)
>>
>> it produces a plot, but I am not sure that this is correct.
>>
>> I have searched for examples, not found anything.  Any help much
>> appreciated.
>>
>> R. Males
>> Cincinnati, Ohio, USA
>>
>> ______________________________________________
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>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>