Displaying 20 results from an estimated 4000 matches similar to: "Weibull"
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
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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2011 Jun 23
2
Confidence interval from resampling
Dear R gurus,
I have the following code, but I still not know how to estimate and extract
confidence intervals (95%CI) from resampling.
Thanks!
~Adriana
#data
penta<-c(770,729,640,486,450,410,400,340,306,283,278,260,253,242,240,229,201,198,190,186,180,170,168,151,150,148,147,125,117,110,107,104,85,83,80,74,70,66,54,46,45,43,40,38,10)
x<-log(penta+1)
plot(ecdf(x),
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
2011 Apr 27
3
MASS fitdistr with plyr or data.table?
I am trying to extract the shape and scale parameters of a wind speed
distribution for different sites. I can do this in a clunky way, but
I was hoping to find a way using data.table or plyr. However, when I
try I am met with the following:
set.seed(144)
weib.dist<-rweibull(10000,shape=3,scale=8)
weib.test<-data.table(cbind(1:10,weib.dist))
2006 Aug 16
3
fitting truncated normal distribution
Hello,
I am a new user of R and found the function dtnorm() in the package msm.
My problem now is, that it is not possible for me to get the mean and sd out of a sample when I want a left-truncated normal distribution starting at "0".
fitdistr(x,dtnorm, start=list(mean=0, sd=1))
returns the error message
"Fehler in "[<-"(`*tmp*`, x >= lower & x <= upper,
2012 Feb 21
5
help error: In dweibull(x, shape, scale, log) : NaNs produzidos
Guys,
I'm having an error when I use the command:
library(MASS)> dados<-read.table("inverno.txt",header=FALSE)> vento50<-fitdistr(dados[[1]],densfun="weibull")Mensagens de aviso perdidas:1: In dweibull(x, shape, scale, log) : NaNs produzidos2: In dweibull(x, shape, scale, log) : NaNs produzidos3: In dweibull(x, shape, scale, log) : NaNs produzidos4: In
2011 Nov 03
1
Fit continuous distribution to truncated empirical values
Hi all,
I am trying to fit a distribution to some data about survival times.
I am interested only in a specific interval, e.g., while the data lies in the interval (0,...., 600), I want the best for the interval (0,..., 24).
I have tried both fitdistr (MASS package) and fitdist (from the fitdistrplus package), but I could not get them working, e.g.
fitdistr(left, "weibull", upper=24)
2008 Jun 13
2
Maximum likelihood estimation in R with censored Data
Hello,
I'm trying to calculate the Maximum likelihood estimators for a dataset
which contains censored data.
I started by using the function "nlm", but isn't there a separate method
for doing this for e.g. the "weibull" and the "log-normal" distribution?
Thanks,
Olivia
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2012 Feb 23
3
why is generating the same graph???
Hi,
why my script iss always generating the same graph?when I change the parameters and the name of text file?
library(MASS)
dados<-read.table("inverno.txt",header=FALSE)
vento50<-fitdistr(dados[[1]],densfun="weibull")
png(filename="invernoRG.png",width=800,height=600)
hist(dados[[1]], seq(0, 18, 0.5), prob=TRUE, xlab="Velocidade
2003 Jul 28
1
Optimization failed in fitting mixture 3-parameter Weibull distri bution using fitdistr()
Dear All;
I tried to use fitdistr() in the MASS library to fit a mixture
distribution of the 3-parameter Weibull, but the optimization failed.
Looking at the source code, it seems to indicate the error occurs at
if (res$convergence > 0)
stop("optimization failed").
The procedures I tested are as following:
>w3den <- function(x, a,b,c)
2004 Nov 23
6
Weibull survival regression
Dear R users,
Please can you help me with a relatively straightforward problem that I
am struggling with? I am simply trying to plot a baseline survivor and
hazard function for a simple data set of lung cancer survival where
`futime' is follow up time in months and status is 1=dead and 0=alive.
Using the survival package:
lung.wbs <- survreg( Surv(futime, status)~ 1, data=lung,
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,
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 Oct 20
1
R code Error : Hybrid Censored Weibull Distribution
Dear Sir/madam,
I'm getting a problem with a R-code which calculate Fisher Information
Matrix for Hybrid Censored Weibull Distribution. My problem is that:
when I take weibull(scale=1,shape=2) { i.e shape>1} I got my desired
result but when I take weibull(scale=1,shape=0.5) { i.e shape<1} it gives
error : Error in integrate(int2, lower = 0, upper = t) : the integral is
probably
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
2004 Sep 23
2
fitting weibull distribution
Dear all,
I get the following error message. And I cannot quite work out what is
wrong. I think the optim gets infinite values. Certainly my data do not
have any infinite values. How can I solve this?
fitdistr(A1, "weibull")
Error in optim(start, mylogfn, x = x, hessian = TRUE, ...) :
non-finite value supplied by optim
I am using R version 1.9.1 on RedHat Linux, Kernel 2.6.8.
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
2010 Jan 28
4
Problems with fitdistr
Hi,
I want to estimate parameters of weibull distribution. For this, I am using
fitdistr() function in MASS package.But when I give fitdistr(c,"weibull") I
get a Error as follows:-
Error in optim(x = c(4L, 41L, 20L, 6L, 12L, 6L, 7L, 13L, 2L, 8L, 22L,
:
non-finite value supplied by optim
Any help or suggestions are most welcomed
--
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2005 May 18
1
'fitdistr' and two views of the same data?
Hello,
I have detailed (with pictures and whatnot) my question on my weblog at
http://www.cs-ed.org/blogs/mjadud/archives/2005/05/a_question_abou.html
The short version of the question is this:
When I ask 'fitdistr' to try and fit my distribution as a "weibull"
distribution, it comes up with some rather wacky parameters.
If I take the same distribution, and do something