Displaying 20 results from an estimated 2000 matches similar to: "Help with function "fitdistr" in "MASS""
2003 Nov 27
2
MASS fitdistr()
Dear R experts,
I am trying to use the R MASS library fitdistr() to fit the following
list:
k21stsList<-c(0.76697,0.57642,0.75938,0.82616,0.93706,0.77377,0.58923,0.37157,0.60796,1.00070,0.97529,0.62858,0.63504,0.68697,0.61714,0.75227,1.16390,0.66702,0.83578)
as follows,
library(MASS)
fitdistr(k21stsList, "normal")
But, I get
Error in fitdistr(k21stsList, "normal") :
2006 Feb 10
8
Fitdistr and MLE for parameter lambda of Poisson distribution
Hello!
I would like to get MLE for parameter lambda of Poisson distribution. I
can use fitdistr() for this. After looking a bit into the code of this
function I can see that value for lambda and its standard error is
estimated via
estimate <- mean(x)
sds <- sqrt(estimate/n)
Is this MLE? With my poor math/stat knowledge I thought that MLE for
Poisson parameter is (in mixture of LaTeX
2005 Nov 02
5
Distribution fitting problem
I am using the MASS library function
fitdistr(x, dpois, list(lambda=2))
but I get
Error in optim(start, mylogfn, x = x, hessian = TRUE, ...) :
Function cannot be evaluated at initial parameters
In addition: There were 50 or more warnings (use warnings() to see the first
50)
and all the first 50 warnings say
1: non-integer x = 1.452222
etc
Can anyone tell me what I am doing
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
[[alternative HTML version deleted]]
2004 Feb 17
2
problem with fitdistr ?
Hi,
I'm trying fitdistr but I'm getting some errors
> fitdistr(rnorm(100),"Normal")
Error in fitdistr(rnorm(100), "Normal") : 'start' must be a named list
> fitdistr(rnorm(100),"Normal",start=list(mean=0,sd=1))
Error in fitdistr(rnorm(100), "Normal", start = list(mean = 0, sd = 1))
:
supplying pars for the Normal is not
2011 May 03
3
fitting distributions using fitdistr (MASS)
Please guide me through to resolve the error message that I get
this is what i have done.
>x1<- rnorm(100,2,1)
>x1fitbeta<-fitdistr(x1,"beta")
Error in fitdistr(x1, "beta") : 'start' must be a named list
Yes, I do understand that sometime for the distribution to converge to the
given set of data, it requires initial parameters of the distribution, to
2007 Sep 09
1
fitdistr()
I am trying to fit the chi-squared distribution to a set of data using the fitdistr function found in the MASS4 library, the data set is called ONES3, I have loaded it using the command
ONES3<-read.table("ONES3.pdf",header=TRUE,na="NA")
I print out the dataset ONES3 to the screen to make sure it has loaded
Then I try to fit this data using the command
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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2008 Feb 09
2
print.fitdistr buglet
Dear developers,
There's a small bug in print.fitdistr that can cause output to be printed
twice, but only if print is called explicitly:
> fit<-fitdistr(rt(1000,3),"t")
There were 11 warnings (use warnings() to see them)
> fit
m s df
-0.02181723 1.00145296 3.13723878
( 0.03865057) ( 0.03999447) ( 0.33298377)
> print(fit)
2003 Jul 25
5
named list 'start' in fitdistr
Hi R lovers!
I'd like to know how to use the parameter 'start' in the function
fitdistr()
obviously I have to provide the initial value of the parameter to optimize
except in the case of a certain set of given distribution
Indeed according to the help file for fitdistr
" For the following named distributions, reasonable starting values
will be computed if `start'
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 Sep 06
4
Cox regression for prevalence estimates
Hello, I'm an MD working in an eye clinic. I'm learning by myself to use R
for use in my research works and for implementation in a software project.
There are some authors who recomends the use of Cox regression as a
substitute for Logistic regression (<a
href="http://www.biomedcentral.com/1471-2288/3/21.pdf"> Barros AJD, Hirakata
VN. BMCMedical Research Methodology, 2003;
2008 Oct 02
4
Load a program at the front end
I want to run a R program, prog.R, interactively. My question is, is
there a way I can start prog.R on the shell terminal when invoking R,
instead of using source() inside R?
TIA,
Gang
2008 Oct 30
1
Is possible, on biological grounds, suggest to fitdistr (MASS library) that the estimated parameters must be between two values?
Sorry if it is a silly question, I haven't found documentation on this and I
don't know if it is possible.
library(MASS) ## for fitdistr
library(msm) ## for dtnorm
#prepare truncated normal distribution
dtnorm0 <- function(x, mean, sd , log = FALSE) {
dtnorm(x, mean, sd, 105, 135, log)
}
set.seed(1)
#Generate normal distribution with the TRUE population mean (day 106 of the
2003 Jul 04
1
Problem with fitdistr for beta
I have the following problem:
I have a vector x of data (0<x<=1 ) with
a U-shaped histogram and try to fit a beta
distribution using fitdistr. In fact,
hist(rbeta(100,0.1,0.1)) looks a lot like
my data.
The equivalent to
the example in the manual
sometimes work:
> a <- rbeta(100,0.1,0.1)
> fitdistr(x=a, "beta", start=list(shape1=0.1,shape2=0.1))1)
> shape1
2006 Sep 23
1
Fitdistr() versus nls()
Hello R-Users,
I'm new to R so I apologize in advance for any big mistake I might
be doing. I'm trying to fit a set of samples with some probabilistic
curve, and I have an important question to ask; in particular I have
some data, from which I calculate manually the CDF, and then I import
them into R and try to fit: I have the x values (my original samples)
and the y values
2005 Nov 17
1
Problem with fitdistr for gamma in R 2.2.0
Dear R developers,
I have encountered strange behaviour of fitdistr for gamma in recent R
build i.e. 2.2.0. I have attached the code for data at the end of this mail
so you can reproduce the problem. In short, I am able to run fitdistr under
2.1.0 without problems, while I get the following error under 2.2.0
(Version 2.2.0 Patched (2005-11-15 r36348))
> fitdistr(otm, "gamma")
Error
2009 Mar 31
5
how to increase the limit for max.print in R
Hi All,
I am using DNAcopy package in R for copy number analysis of 500K chip.
The final output which I get from DNA copy is too big to be printed in a
file.
So I am getting an error as "reached getOption("max.print") -- omitted
475569 rows "
Can somebody please provide me the pointers with how to increase the limit
for max.print .
Thanks,
Pooja
DISCLAIMER\
2009 May 13
2
Help with a cumullative Hazrd Ratio plot
Hi R-masters
I need help to make modified cumulative hazard ratio plot.
I need create a common plot but with the number of subjects in risk each
ticks times for two different groups in bottom of plot (I put one
example in attach).
Do you know a routine for this?
Is possible create a routine for this?
In this case with how commands?
Thanks in advance!
--
Bernardo Rangel Tura, M.D,MPH,Ph.D
2005 Jul 12
1
three par. fitting with fitdistr
Hello,
I want to fit a tree parameter distribution to given data. I tried it with
sample data using the "fitdistr" function.
Here my workflow that didn't had any result:
I started with the generalized gamma distr, which is:
r*dgamma(x^r,shape,rate)
The R-function is:
ggamma = function (x,r,shape,rate) r*dgamma(x^r,shape,rate=rate)
For the first step I assumed r = 1 and I