Displaying 20 results from an estimated 7000 matches similar to: "On Corrections for Chi-Sq Goodness of Fit Test"
2000 Nov 03
1
Chi-square Goodness of Fit Test
Dear R-users,
is there a function for the Chi-square Goodness of Fit Test in R
(compare function chisq.gof in S/S-PLUS).
Thanks for help.
Matthias Seitzinger
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2009 Feb 04
3
chi squared goodness of fit test with R
Dear R users,
I am a master student in Mathematics and I am writing my thesis in
statistics. I need to use R and unfortunately I do not have any experience
with a computer program. Could you please help me about chi squared goodness
of fit test with R? In R-help website I saw a message about how to do that
but I do not know how to cut the data into bins and calculate the expected
numbers in each
2010 Mar 10
2
Test chi cuadrado de bondad de ajuste
Hola,
con vistas a docencia, me gustaría saber si hay alguna librería que
haga el test de la chi cuadrado para variables continuas, que no sean
la normal.
Lo encontré para variables discretas y para la normal. También,
obviamente, se puede hacer un pequeño programa que lo calcule "como a
mano", pero a los alumnos les obliga a entrar en detalles de
programación... :-/
La idea sería
2010 Jul 07
1
Different goodness of fit tests leads to contradictory conclusions
I am trying to test goodness of fit for my legalistic regression using several options as shown below. Hosmer-Lemeshow test (whose function I borrowed from a previous post), Hosmer–le Cessie omnibus lack of fit test (also borrowed from a previous post), Pearson chi-square test, and deviance test. All the tests, except the deviance tests, produced p-values well above 0.05. Would anyone please
2006 Jun 02
1
geoR, plot of variog4 lines incomplete
I'm using R for Mac OSX version 1.14 (2129) and the geoR package
version 1.6-5 (the current version in the R repository). I'm running
R in OS 10.4.6 on a Mac G4 iBook (933MHz, 640 MB DDR SDRAM). I
searched the R archive and did not find a posting on this issue.
I want to use the variog and variog4 functions of geoR to
characterize the pattern of spatial autocorrelation of tree
2011 Nov 20
2
ltm: Simplified approach to bootstrapping 2PL-Models?
Dear R-List,
to assess the model fit for 2PL-models, I tried to mimic the
bootstrap-approach chosen in the GoF.rasch()-function. Not being a
statistician, I was wondering whether the following simplification
(omit the "chi-squared-expressed model fit-step") would be appropriate:
GoF.ltm <- function(object, B = 50, ...){
liFits <- list()
for(i in 1:B){
rndDat <-
2010 Jun 01
2
Mid-P value for a chi-squared test
Can anyone tell me how to calculate a mid-p value for a chi-squared test
in R?
Many thanks,
Andrew Wilson
2001 Oct 26
3
warnings --- wish/bug (PR#1148)
When R prints warnings, they often go "out of the line", it would be
better if they where wrapped with
writeLines(strwrap ...
I tried to do that , changing the function warnings, but it has only
effect when called explicitely, not when R prints the warnings unasked.
Anyhow, here is the changed warnings:
warnings <-
function (...)
{
if (!(n <- length(last.warning)))
2008 Mar 10
1
ltm package question
Hello All,
I was wondering how I can get the overall Pearson chi^2 test of model fit
with its df and p value in the LTM package for the 2PL models.
Thanks,
--
Davood Tofighi
Department of Psychology
Arizona State University
[[alternative HTML version deleted]]
2012 Dec 03
4
Chi-squared test when observed near expected
Dear UseRs,
I'm running a chi-squared test where the expected matrix is the same as the
observed, after rounding. R reports a X-squared of zero with a p value of
one. I can justify this because any other result will deviate at least as
much from the expected because what we observe is the expected, after
rounding. But the formula for X-squared, sum (O-E)^2/E gives a positive
value. What
2011 Apr 22
1
Create 2x2 table from summary data and run chi square test.
R 2.12
windows 7
I am summary data that I would like to make into a 2x2 table representing counts positive vs. negative counts:
28/289 20/276
My table should look something like the following:
group1 group2
Positive 28 20
Negative 289 276
How can a (1) create the 2x2 table
(2) run a chi square test on the table?
I have tried the following code, but I
2006 Jun 30
2
Query : Chi Square goodness of fit test
I want to calculate chi square test of goodness of fit to test,
Sample coming from Poisson distribution.
please copy this script in R & run the script
The R script is as follows
########################## start
#########################################
No_of_Frouds<-
c(4,1,6,9,9,10,2,4,8,2,3,0,1,2,3,1,3,4,5,4,4,4,9,5,4,3,11,8,12,3,10,0,7)
N <- length(No_of_Frouds)
# Estimation of
2005 Sep 13
1
Fisher's exact test vs Chi-square
Timothy,
I believe you are mistaken. Fisher's exact test give the correct answer
even in the face of small expected values for the cell counts. Pearson's
Chi-square approximates Fisher's exact test and can give the wrong
answer when expected cell counts are low. Chi-square was developed
because it is computationally "simple". Fisher's exact test,
particularly with tables
2001 Dec 18
4
chi-squared test
I don't quite understand the difference between the two methods for
performing a chi-squared test on contingency tables: summary(table())
and chisq.test()
They may different results. E.g.:
aa <- gl(2, 10)
bb <- as.factor(c(1,2,2,2,1,2,1,2,2,2,1,2,2,2,1,1,1,2,1,1))
aa <- c(aa, aa)
bb <- c(bb, bb)
table(aa, bb)
summary(table(aa, bb))
chisq.test(aa, bb)
Could somebody give me
2008 Jan 07
2
chi-squared with zero df (PR#10551)
Full_Name: Jerry W. Lewis
Version: 2.6.1
OS: Windows XP Professional
Submission from: (NULL) (24.147.191.250)
pchisq(0,0,ncp=lambda) returns 0 instead of exp(-lambda/2)
pchisq(x,0,ncp=lambda) returns NaN instead of exp(-lambda/2)*(1 +
SUM_{r=0}^infty ((lambda/2)^r / r!) pchisq(x, df + 2r))
qchisq(.7,0,ncp=1) returns 1.712252 instead of 0.701297103
qchisq(exp(-1/2),0,ncp=1) returns 1.238938
2001 Feb 07
3
Goodness of fit to Poisson / NegBinomial
All,
I have some data on parasites on apple leaves and want to do a
goodness of fit test to a Poisson distribution. This seems to
do it:
mites <- c(rep(0,70),
rep(1,38),
rep(2,17),
rep(3,10),
rep(4,9),
rep(5,3),
rep(6,2),
rep(7,1))
tab <- table(mites)
NSU <- length(mites)
N <-
2007 May 18
1
Goodness-of-fit test for gamma distribution?
Hi all,
I am wondering if anyone has written (or knows of) a function that
will conduct a goodness-of-fit test for a gamma distribution. I am
especially interested in test statistics have some asymptotic
parametric distribution that is independent of sample size or values
of fitted parameters (e.g., a chi-squared distribution with some
fixed df), because I want to fit gamma distributions to
2007 Mar 03
3
How to convert List object to function arguments?
Dear R gurus,
I have a function "goftests" that receives the following arguments:
* a vector "x" of data values;
* a distribution name "dist";
* the dots list ("...") containing a list a parameters to pass to CDF
function;
and calls several goodness-of-fit tests on the given data values against
the given distribution.
That is:
##### BEGIN CODE SNIP #####
2005 Aug 13
1
Penalized likelihood-ratio chi-squared statistic: L.R. model for Goodness of fit?
Dear R list,
From the lrm() binary logistic model we derived the G2 value or the
likelihood-ratio chi-squared statistic given as L.R. model, in the output of
the lrm().
How can this value be penalized for non-linearity (we used splines in the
lrm function)?
lrm.iRVI <- lrm(arson ~ rcs(iRVI,5),
penalty=list(simple=10,nonlinear=100,nonlinear.interaction=4))
This didn’t work
2004 Jul 06
3
Improving effeciency - better table()?
Hi,
I've been running some simulations for a while and the performance of R
has been great. However, I've recently changed the code to perform a sort
of chi-square goodness-of-fit test. To get the observed values for each
cell I've been using table() - specifically I've been using cut2 from
Hmisc to divide up the range into a specified number of cells and then
using