[R] fitdistr for t distribution

lagreene lagreene101 at gmail.com
Fri May 15 13:22:59 CEST 2009


Thanks Jorge,

but I still don't understand where they come from.  when I use: 
fitdistr(mydata, "t", df = 9) and get values for m and s, and the variance
of my data should be the df/s?

I jsut want to be able to confirm how m and s are calculated

mydt <- function(x, m, s, df) dt((x-m)/s, df)/s
fitdistr(x2, mydt, list(m = 0, s = 1), df = 9, lower = c(-Inf, 0))

Thanks anyway for the help!




Jorge Ivan Velez wrote:
> 
>  Dear lagreene,
> See the second example in
> 
> require(MASS)
> ?fitdistr
> 
> HTH,
> 
> Jorge
> 
> 
> On Thu, May 14, 2009 at 7:15 PM, lagreene <lagreene101 at gmail.com> wrote:
> 
>>
>> Hi,
>> I was wondering if anyone could tell me how m and s are calculated for a
>> t
>> distribution?
>>
>> I thought m was the sample mean and s the standard deviation- but
>> obviously
>> I'm wrong as this doesn'y give the same answer.
>>
>> Thank you
>> --
>> View this message in context:
>> http://www.nabble.com/fitdistr-for-t-distribution-tp23550779p23550779.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> 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.
>>
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> 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.
> 
> 

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