[R] calculate quantiles of a custom function

[Albyn Jones]

What do quantiles mean here?  If you have a mixture density, say

    myf <- function(x,p0) p0*dbeta(x,2,6) + (1-p0)*dbeta(x,6,2)

then I know what quantiles mean.  To find the Pth quantile use uniroot  
to solve for the x such that myf(x,p0) - P =0.

albyn

Quoting VictorDelgado <victor.maia at fjp.mg.gov.br>:

>
> Gerhard wrote
>>
>>
>> Suppose I create a custom function, consisting of two beta-distributions:
>>
>> myfunction <- function(x) {
>>   dbeta(x,2,6) + dbeta(x,6,2)
>> }
>>
>> How can I calculate the quantiles of myfunction?
>>
>> Thank you in advance,
>>
>> Gerhard
>>
>>
>
> Gehard, if do you want to know the quantiles of the new distribution created
> by "myfunction". Maybe you can also do:
>
> x <- seq(0,1,.01) # insert your 'x'
> q <- myfunction(x)
> # And:
> quantile(x)
>
>       0%      25%      50%      75%     100%
> 0.000000 1.476177 2.045389 2.581226 2.817425
>
> # This gives the sample quantiles. You can also look foward to simulations
> (like Bert Gunter had suggested) to know better the properties of
> distributions quantiles obtained after 'myfunction'.
>
>
>
> -----
> Victor Delgado
> cedeplar.ufmg.br P.H.D. student
> www.fjp.mg.gov.br reseacher
> --
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