Displaying 20 results from an estimated 20000 matches similar to: "Fitting a distribution involving a cusum"
2010 Mar 07
2
questions about "Cusum"
Dear friends:
I have just read an article entitled " Monitoring of nosocomial invasive aspergillosis and early evidence of an outbreak using cumulative sum tests (CUSUM)", which is published in "Clinical Microbiology and Infection". We have great need to estimate the fluctuation of incidence of IFI in our hospital. But I don't know the details of the stastical method and
2008 Feb 22
1
fitting a lognormal distribution using cumulative probabilities
Dear all,
I'm trying to estimate the parameters of a lognormal distribution fitted
from some data.
The tricky thing is that my data represent the time at which I recorded
certain events. However, in many cases I don't really know when the event
happened. I' only know the time at which I recorded it as already happened.
Therefore I want to fit the lognormal from the cumulative
2005 Jan 11
1
CUSUM SQUARED structural breaks approach?
Dear all,
Does anyone know where there is R or S code for the CUSUM SQUARED
structural breaks approach? (Brown, Durban and Evans, 1975 - used in
Pesaran and Timmerman, 2002)
The problem is that the breaks package only appears to offer the
standard 'unsquared' CUSUM, even though it appears most think it is
inferior to the squared version. It might appear to be a relatively
simple
2004 Jul 26
1
qcc package & syndromic surveillance (multivar CUSUM?)
Dear R Community:
I am working on a public health early warning system, and
I see that the qcc package allows for CUSUM and other statistical quality tests
but I am not sure if my project is a good match for qcc functions as written.
Any advice you may have is very much appreciated.
I have four years worth of daily counts of emergency room admissions for
different conditions (e.g. respiratory,
2009 Oct 30
1
R strucchange question: recursive-based CUSUM
Hello R users:
I'm trying now to apply the package strucchange to see whether there is
a structural change in linear regression. I have noted the following
problem that arises in my case with recursive-based CUSUM: generic
function recresid() in efp() generates an error, since (probably) it
cannot compute the inverse matrix of (X^(i-1)^T)*(X^(i-1)) at each step
(i-1), because the matrix
2009 Mar 16
1
Fw: Fitting GUMBEL Distribution - CDF function and P P Plot
Dera R Helpers,
I am re-posting my query.
Please guide me.
Maithili
--- On Fri, 3/13/09, Maithili Shiva <maithili_shiva at yahoo.com> wrote:
I am trying to fit the Gumbel distribution to a data. I am
using lmom package. I am getting problem in Cumulative
Distribution Function of Gumbel distribution as I am getting
it as a series of 0's and 1's thereby affecting the
P P
2007 Feb 27
1
fitting the gamma cumulative distribution function
Hi.
I have a vector of quantiles and a vector of probabilites that, when
plotted, look very like the gamma cumulative distribution function. I
can guess some shape and scale parameters that give a similar result,
but I'd rather let the parameters be estimated. Is there a direct way
to do this in R?
Thanks,
Tim.
week <- c(0,5,6,7,9,11,14,19,39)
fraction <-
2009 Mar 13
0
Fitting GUMBEL Distribution - CDF function ISSUE
Dear R helpers
I am trying to fit the Gumbel distribution to a data. I am using lmom package. I am getting problem in Cumulative Distribution Function of Gumbel distribution as I am getting it as a series of 0's and 1's thereby affecting the P P Plot. My R code is as follows.
library(quantreg)
library(RODBC)
library(MASS)
library(actuar)
library(lmom)
x <-
2005 Oct 27
1
Fitting of Non-Linear Diff Equations and Parameter Estimation
Hello Everybody,
I am running R 2.2.0 with Windows XP
i am trying to fit nonlinear differential equation to data sets which looks
like this:
Week N C
0 1 1
1 5 6
2 6.2 12.2
3 59 71.2
4 39 110.2
5 38 148.2
6 44 192.2
7 20.4 212.6
8 19.4 232
9 34.2 266.2
10 35.4 301.6
and i need to fit these data to the following diff equation:
dNdt=a*N-b*N*C, dCdt=N^2,
Where a=birth rate, b=death rate and N=
2007 Jul 04
1
Long-tail model in R ... anyone?
Dear all,
first I would like to tell you that I've been using R for two days... (so,
you can predict my knowledge of the language!).
Yet, I managed to implement some stuff related with the Long-Tail model [1].
I did some tests with the data in table 1 (from [1]), and plotted figure 2
(from [1]). (See R code and CSV file at the end of the email)
Now, I'm stuck in the nonlinear regression
2011 Mar 15
3
fitting a distribution to a ecdf plot
Dear all,
I need to plot an cumulative distribution plot of a variable and then to fit a distribution to that, probably a weibull or lognormal.
I have plotted the ecdf as
> plot(ecdf(x))
but I haven't managed to fit the distribution. I have as well attached the data.
I would appreciate if you could help me on that.
Thank you.
Kind regards
Maria
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2002 Dec 16
1
Partial Sums
Is it possible to calculate partial sums in R?
I have the equation:
Px = (k / x) * SUM_{from j >= x to infinity} Pj x=1,2,3,...
where k is a parameter, Pj is the Poisson probability, and x is a rank.
(This is for rank-frequency data.) In other words, the frequency of an
entity at rank x depends on the sum of frequencies of all entities at
ranks j > x.
Many thanks,
Andrew
2011 Oct 11
1
singular gradient error in nls
I am trying to fit a nonlinear regression to infiltration data in order to
determine saturated hydraulic conductivity and matric pressure. The
original equation can be found in Bagarello et al. 2004 SSSAJ (green-ampt
equation for falling head including gravity). I am also VERY new to R and
to nonlinear regressions. I have searched the posts, but am still unable to
determine why my data come up
2003 Nov 25
5
Parameter estimation in nls
I am trying to fit a rank-frequency distribution with 3 unknowns (a, b
and k) to a set of data.
This is my data set:
y <- c(37047647,27083970,23944887,22536157,20133224,
20088720,18774883,18415648,17103717,13580739,12350767,
8682289,7496355,7248810,7022120,6396495,6262477,6005496,
5065887,4594147,2853307,2745322,454572,448397,275136,268771)
and this is the fit I'm trying to do:
nlsfit
2008 Jan 25
1
Need Advice with C# Program to Create and Display Cusum Chart
I need to write a C# program to create and display Cusum chart from any
of the packages,
spc, qcc or strucchange.
Issues:
1-The data resides in a MS SQL Database. The C# program will handle
obtaining the data for the requisite types of samples.
Assistance needed on:
1-How can I call the cusum capabilities of any of the above packages
and pass the data to the cusum function and plot?
2-How
2001 Jan 24
1
CuSum & V-Mask
Good Afternoon,
I am currently writing a program to perform a cusum with v-mask and since I
am experiencing a few problems, was wondering if there is something similar
in existance?
Many thanks in advance,
Gavin McCabe
Gavin McCabe
University of Strathclyde
Department of Statistics & Modelling Science
Livingstone Tower (Rm. L7.47)
26 Richmond Street
GLASGOW
G1 1XH
U.K.
Tel.: +44
2010 Sep 27
1
One-sided CUSUM / MOSUM Tests?
Dear R-help list members,
I have the following question concerning the strucchange()-package: is
it possible to get the boundaries for one-sided (upper / lower) CUSUM
and MOSUM tests?
Thank you in advance.
Julia
2004 Sep 04
0
Non-Markovian Behaviour of a Cusum?
Can someone help me understand simulations of a one-sided Cusum?
Consider the following:
Q[i] = max(0, Q[i-1]+z[i]), z[i] ~ N(offset, 1), with Q[0] = FIR
(fast initial response).
With offset < 0, mean{Q[i] for fixed i averaged over many
simulations} approaches an asymptote as i -> Inf. In simulations with
abs(offset) small and FIR close to the asymptote, Q[i]
2009 Jan 12
1
Help with storage of each matrix generated in a loop
I need to store each matrix generated in a loop.
I've been working with the CUSUM algorithm and I've been trying to implement
it in R.
What I need to do with my dataset is to create 1000 randomized datasets and
cumulative sum them all and store all of those randomized CUSUMed datasets
for further analysis and creation of the simulation envelope in the CUSUM
chart. But I can't manage
2003 Nov 17
4
cumulative distribution functions
hi y'all,
I am wondering if there is any special command, function,
package, etc to help me doing a cumulative distribution function,
with y-scale - probability scale.
I tried the help in R and i got the following answers:
cumsum(base) Cumulative Sums, Products, and Extremes
ecdf(stepfun) Empirical Cumulative Distribution Function
cpgram(ts) Plot