Am Dienstag, 3. Januar 2012, 19:51:36 schrieb Prof. Dr. Matthias Kohl:
D - AbscontDistribution(d = function(x) dbeta(x, 2, 6) + dbeta(x,6,2),
low = 0, up = 1, withStand = TRUE)
Dear all,
thank you all again for your help.
So, summing up, (in case this might be useful to other beginners -
FWIW, the integral of a mixture density is the same mixture of the
CDFs, so you can use the pbeta functions:
pcustom - function(x) (pbeta(x,2,6) + pbeta(x,6,2))/2
albyn
Quoting Gerhard felds...@gmx.net:
Am Dienstag, 3. Januar 2012, 19:51:36 schrieb Prof. Dr. Matthias Kohl:
D -
Hi,
I guess that my problem has an obvious answer, but I have not been able to
find it.
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?
I have not seen any
Gerhard:
Strictly speaking, it's quantiles of a custom distribution, not function.
There may be some way to handle your example easily, but, in general,
you would need to solve the resulting integral equation. This is hard
-- closed form solutions rarely exist; good approximations require
work.
On Jan 3, 2012, at 7:24 AM, Gerhard wrote:
Hi,
I guess that my problem has an obvious answer, but I have not been
able to
find it.
Suppose I create a custom function, consisting of two beta-
distributions:
myfunction - function(x) {
dbeta(x,2,6) + dbeta(x,6,2)
}
Given the symmetry
Am Dienstag, 3. Januar 2012, 11:05:11 schrieben Sie:
The quick way is to look at the structure with 'str':
str(integrate(myfunction,0,.9))
List of 5
$ value : num 1.85
$ abs.error : num 2.05e-14
$ subdivisions: int 1
$ message : chr OK
$ call: language
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
VictorDelgado wrote
quantile(x)
Correcting to
quantile(q)
-
Victor Delgado
cedeplar.ufmg.br P.H.D. student
www.fjp.mg.gov.br reseacher
--
View this message in context:
http://r.789695.n4.nabble.com/calculate-quantiles-of-a-custom-function-tp4256887p4257575.html
Sent from the R
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
On 03/01/2012 1:33 PM, Albyn Jones wrote:
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.
You
Dear Gerhard,
you could also use package distr; e.g.
library(distr)
## use generating function AbscontDistribution
D - AbscontDistribution(d = function(x) dbeta(x, 2, 6) + dbeta(x,6,2),
low = 0, up = 1, withStand = TRUE)
## quantiles
q(D)(seq(0,1,0.1))
Best
Matthias
On 03.01.2012 19:33,
Am Dienstag, 3. Januar 2012, 08:50:44 schrieb VictorDelgado:
VictorDelgado wrote
quantile(x)
Correcting to
quantile(q)
-
Dear Victor,
thank you for your answer.
Best,
Gerhard
Victor Delgado
cedeplar.ufmg.br P.H.D. student
www.fjp.mg.gov.br reseacher
--
View this message
right. replace dbetas with pbetas.
albyn
Quoting Duncan Murdoch murdoch.dun...@gmail.com:
On 03/01/2012 1:33 PM, Albyn Jones wrote:
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
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