Displaying 20 results from an estimated 3000 matches similar to: "Fitting my data to a Weibull model"
2010 Aug 23
1
Fitting Weibull Model with Levenberg-Marquardt regression method
Hi,
I have a problem fitting the following Weibull Model to a set of data.
The model is this one: a-b*exp(-c*x^d)
If I fitted the model with CurveExpert I can find a very nice set of coefficients which create a curve very close to my data, but when I use the nls.lm function in R I can't obtain the same result.
My data are these:
X Y
15 13
50 13
75 9
90 4
With the commercial
2009 Apr 30
1
finite mixture model (2-component Weibull): plotting Weibull components?
Dear Knowledgeable R Community Members,
Please excuse my ignorance, I apologize in advance if this is an easy question, but I am a bit stumped and could use a little guidance.
I have a finite mixture modeling problem -- for example, a 2-component Weibull mixture -- where the components have a large overlap, and
I am trying to adapt the "mclust" package which concern to normal
2008 Jul 07
4
script.aculo.us slider - this and event handler - depending sliders
Hi,
I successfully created depending sliders with prototype and slider.js.
See the result here: http://www.soa-world.de/dev/slider/slider.html
(here''s the code: http://pastebin.com/ma1e82eb)
There is one problem with my code. What I do is I have a sliders class
"function sliders()"
inside I create the 5 sliders in a for loop and store them inside an
array which is a member of
2012 Feb 21
3
HELP ERROR Weibull values must be > 0
GUYS,
I NEED HELP WITH ERROR:
library(MASS)
> dados<-read.table("mediaRGinverno.txt",header=FALSE)
> vento50<-fitdistr(dados[[1]],densfun="weibull")
Erro em fitdistr(dados[[1]], densfun = "weibull") :
Weibull values must be > 0
WHY RETURN THIS ERROR? WHAT CAN I DO?
BEST REGARDS
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2002 Dec 18
2
weibull test
Hello
What is the appropriate method to test if a given distribution is a
weibull
thank you
meriema
email
meriema.belaidouni at int-evry.fr
2005 Nov 22
3
Weibull and survival
Hi
I have been asked to provide Weibull parameters from a paper using
Kaplan Meir survival analysis.
This is something I am not familiar with.
The survival analysis in R works nicely and is the same as commercial
software (only the graphs are superior in R).
The Weibull does not and produces an error (see below).
Any ideas why this error should occur?
My approach may be spurious.
2002 Jan 17
1
weibull in R
Hi all
I try to make a weibull survival analysis on R.
I know make this on GLIM, and now I try to make the GLIM exercice GLEX8 on R
to learning and compare the test.
The variables are:
time censor group bodymass
In GLIM I make:
$calc %s=1 $ to fit weibull rather than exponential
$input %pcl weibull $
$macro model group*bodymass $endmac$
$use weibull t w %s $
Then, GLIM estimate an alpha for the
2001 Aug 28
2
Estimating Weibull Distribution Parameters - very basic question
Hello,
is there a quick way of estimating Weibull parameters for some data points
that are assumed to be Weibull-distributed?
I guess I'm just too lazy to set up a Maximum-Likelihood estimation...
...but maybe there is a simpler way?
Thanks for any hint (and yes, I've read help(Weibull) ;)
Kaspar Pflugshaupt
--
Kaspar Pflugshaupt
Geobotanical Institute
ETH Zurich, Switzerland
2005 Jun 09
2
Weibull survival modeling with covariate
I was wondering if someone familiar
with survival analysis can help me with
the following.
I would like to fit a Weibull curve,
that may be dependent on a covariate,
my dataframe "labdata" that has the
fields "cov", "time", and "censor". Do
I do the following?
wieb<-survreg(Surv(labdata$time,
labadata$censor)~labdata$cov,
2004 Mar 19
5
loop through files in a dir
Hello
I have data in many files in a directory, how can I
loop through the files in a given dir in-order-to
build a data.frame?
thanks
2006 Sep 21
1
survival function with a Weibull dist
Hi
I am using R to fit a survival function to my data
(with a weibull distribution).
Data: Survival of individuals in relation to 4
treatments ('a','b','c','g')
syntax:
---- > survreg(Surv(date2)~males2, dist='weibull')
But I have some problems interpreting the outcome and
getting the parameters for each curve.
--------- Value Std.
2008 Oct 22
2
Weibull parameter estimation
Dear R-users
I would like to fit weibull parameters using "Method of moments" in order to
provide the inital values of the parameter to de function 'fitdistr' . I
don`t have much experience with maths and I don't know how to do it.
Can anyone please put me in the rigth direction?
Borja
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2011 Sep 14
2
Weibull point process
Dear list,
I'm looking for a function to generate (simulate) a random Weibull
point process. Can anyone help?
Cheers,
Torbj?rn Ergon, University of Oslo
2011 Oct 28
1
weibull fitdistr problem: optimization failed
I'm getting errors when running what seems to be a simple Weibull
distribution function:
This works:
x <-
c(23,19,37,38,40,36,172,48,113,90,54,104,90,54,157,51,77,78,144,34,29,45,16,15,37,218,170,44,121)
rate <- c(.01,.02,.04,.05,.1,.2,.3,.4,.5,.8,.9)
year <- c(100,50,25,20,10,5,3.3,2.5,2,1.2,1.1)
library(MASS)
x <- sort(x)
tryCatch(
f<-fitdistr(x, 'weibull'),
error
2002 Aug 06
2
Estimating Weibull parameters
Hi R-Community,
I have a vector of Weibull distributed observations and I would like to
estimate the parameters "shape" and "scale" of the Weibull distribution.
Is there a way to do this in R?
Much thanks in advance,
Hagen Schm?ller
--
-----------------------------------------------------------------------
Dipl.-Ing. Hagen K. Schm?ller
Institut f?r Elektrische Anlagen und
2001 Jul 02
1
nls newbie: help approximating Weibull distribution
Hi folks,
I tried to retain the Weibull distribution using the `nls' function
and proceeding along the lines of the example provided in the
`SSweibull' help (at least I thought so):
t <- (1:200)/100
v <- pweibull(t, shape=3, scale=1)
df <- data.frame(Time=t, Value=v)
Asym <- 1.0; Drop <- 1.0; lrc <- 0; pwr <- 1
df.estimate <- nls(Value ~ SSweibull(Time,
2005 Nov 24
4
Survreg Weibull lambda and p
Hi All,
I have conducted the following survival analysis which appears to be OK
(thanks BRipley for solving my earlier problem).
> surv.mod1 <- survreg( Surv(timep1, relall6)~randgrpc, data=Dataset,
dist="weibull", scale = 1)
> summary(surv.mod1)
Call:
survreg(formula = Surv(timep1, relall6) ~ randgrpc, data = Dataset,
dist = "weibull", scale = 1)
2004 Jan 14
1
estimation of lambda and gamma with std errors for a weibull model
Dear R experts,
How should lambda and gamma (with std.errors) be calculated for a weibull model with age as an independent predictor? I have assumed that this can be done with survreg with e. g. (summary(survreg(Surv(time, status) ~ age, dist = 'weibull')) ) and predict.survreg with e.g. (predict(model, se.fit = T, newdata = data.frame(age = seq(50, 80, 5)) but unfortunately I'm
2008 Oct 07
3
Fitting weibull, exponential and lognormal distributions to left-truncated data.
Dear All,
I have two questions regarding distribution fitting.
I have several datasets, all left-truncated at x=1, that I am attempting
to fit distributions to (lognormal, weibull and exponential). I had
been using fitdistr in the MASS package as follows:
fitdistr<-(x,"weibull")
However, this does not take into consideration the truncation at x=1. I
read another posting in this
2009 Jun 05
3
Fitting a Weibull Distribution
How do you fit a Weibull distribution in R?