Displaying 20 results from an estimated 1000 matches similar to: "Comparison of two weibull distributions"
2013 Oct 28
0
"Optimization fail" error from fitdistr (Weibull distribution)
Hello everyone,
This is Kangmin.
I am trying to produce shape and scale of my wind data. My data is based on
wind speed frequency with 1km/hr increment. data is described below.
Windspeed (km/h) Frequency
1 351
2 147
3 317
4 378
5 527
6 667
7 865
8 970
9 987
10 907
11 905
12 642
13 1000
14 983
15 847
16 842
17 757
18 698
19 632
20 626
21 599
22 529
23 325
24 391
2011 May 20
1
grep pattern
Hi all,
I'm trying to subset a pattern in a vector. Each argument has 6
letters, and I need those that start with Z and end with Z.
e.g.
x <- c("ZFHSJK", "ZFHJKZ","ZIOPWE","ZLKJSD","ZKFLPZ")
I've looked up other discussions but still can't seem to find the
answer.
Thanks.
Kangmin
2008 Oct 28
2
Fitting weibull and exponential distributions to left censoring data
Dear R-users
I have some datasets, all left-censoring, and I would like to fit
distributions to (weibull,exponential, etc..). I read one solution using the
function survreg in the survival package. i.e
survreg(Surv(...)~1, dist="weibull") but it returns only the scale
parameter.
Does anyone know how to successfully fit the exponential, weibull etc...
distributions to left-censoring
2012 Mar 05
1
Fitting & evaluating mixture of two Weibull distributions
Hello,
I would like to fit a mixture of two Weibull distributions to my data, estimate the model parameters, and compare the fit of the model to that of a single Weibull distribution.
I have used the mix() function in the 'mixdist' package to fit the mixed distribution, and have got the parameter estimates, however, I have not been able to get the log-likelihood for the fit of this model
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
2005 Aug 10
2
Exponential, Weibull and log-logistic distributions in glm()
Dear R-users!
I would like to fit exponential, Weibull and log-logistic via glm() like
functions. Does anyone know a way to do this? Bellow is a bit longer
description of my problem.
Hm, could family() be adjusted/improved/added to allow for these distributions?
SAS procedure GENMOD alows to specify deviance and variance functions to
help in such cases. I have not tried that option and I do not
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
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
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
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.
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,
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
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.
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
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
2009 Jun 05
3
Fitting a Weibull Distribution
How do you fit a Weibull distribution in R?