Displaying 20 results from an estimated 3000 matches similar to: "In chisq.test(x) : Chi-squared approximation may be incorrect"
2008 Jan 13
2
Retrieve only part of a matrix
Hi All,
I'm new with R; this is a basic question. I was given a matrix I of (nrow,
ncol), I would like to create another matrix A with some data in the matrix
I, say [1,4] (row 1, column 4) to [271,19000] (row 271, column 19000). How
do I do this? Please help. Thank you very much.
--mc
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2007 Jul 25
1
Rgraphviz and R 2.5.1 entry point Rf_allocString could not be located
Dear R-Helpers
In R 2.5.1, the command library(Rgraphviz) fails on my Windows (XP SP2)
system with error popup "The procedure entry point Rf_allocString could not
be located in the dynamic link library R.dll".
Thanks in advance for any suggestion in solving the error.
My D. Coyne
Imagination is more important than knowledge... (Albert Einstein)
mcoyne@boninc.com
2008 Mar 02
1
Could not install aroma.affymetrix
I don't know if this is the correct forum to ask the following question;
however, when I search the aroma.affymetrix discussion group, it suggested
that I should posted the question to r-help. Here it goes.
I followed the instructions on aroma.affymetrix trying to install the
packages; following are the steps:
> install.packages(c("R.oo", "R.utils"),
2008 Jan 13
4
For Loop performance
Hello,
Newbie question and hope you can help .
I have two vector V1 and V2, where length(V2) = length of (V1) * 2;
length(V1) ~ 16,000.
For each member in V1, I need to compare 2 element of V2 for equality
i.e.
for (I in 1:length (V1)) {
if ( v2[i] == v1[i] & v2[i+1]==v1[i] ){
statement_1
statement_2
.
}
}
This for-loop is too slow
2008 Feb 13
2
How to handle Which on two matrices that do not have same number of rows
R-newbie question
I have 2 matrices
(a) P1 has only one column of 32K rows
(b) PC has 2 column {P, C} of 3200 rows
Every values in P1 matches with a value in PC[,p] (column p). I would like
to use Which to search for all value in P1 that matchex PC[,p] and get the
PC[,c]. However because P1 and PC does not have the same number of rows, I
got lots of 'NA'. Thanks for your
2008 Feb 02
2
Ignore error t.test in a loop
Hi,
I place a t.test in a loop and would like to continue to process the loop
even when t.test encounter error. How do I do that? For example, in one
iteration, the data is completely constant and t.test gives error, the
entire program terminates. I would like to write the information out to a
file, and the loop should continue.
Thanks
My D. Coyne
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2006 Dec 02
1
Chi-squared approximation may be incorrect in: chisq.test(x)
I am getting "Chi-squared approximation may be incorrect in:
chisq.test(x)" with the data bleow.
Frequency distribution of number of male offspring in families of size 5.
Number of Male Offspring N
0 518
1 2245
2 4621
3 4753
4 2476
5
2008 Jan 15
1
Retrieve results from chisq.test programmatically
Hello,
I would like to run a series of chisq.test() and store results (x-square,
df, p-value) in a matrix for further analysis, but don't know how to do
such. Currently I run the command line for each set of data at a time and
it is time consuming.
Thank you for your help.
--My Coyne
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2012 Jun 04
1
Chi square value of anova(binomialglmnull, binomglmmod, test="Chisq")
Hi all,
I have done a backward stepwise selection on a full binomial GLM where the
response variable is gender.
At the end of the selection I have found one model with only one explanatory
variable (cohort, factor variable with 10 levels).
I want to test the significance of the variable "cohort" that, I believe, is
the same as the significance of this selected model:
>
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
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
2009 Nov 05
1
partitioning chi-square statistic (g squared)
hi all -
is there a package or library that contains a function for partitioning the
chi-square statistic of an I X J contingency table into its respective
independent parts?
i looked around for this, but i didn't find anything. perhaps there's
another name for this sort of analysis? i know it as "g-squared".
thanks,
chris.
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2006 Nov 08
2
Chi-squared test (PR#9350)
Full_Name: Sahotra Sarkar
Version: 2.2.0
OS: Windows XP
Submission from: (NULL) (128.83.34.44)
This is not a bug: I'm just wondering why chisq.test does not allow the
specification of the degree of freedom (df).
2005 Nov 24
2
Chi-squared test
Hello,
I'm trying to calculate a chi-squared test to see if my data are
different from the theoretical distribution or not:
chisq.test(rbind(c(79, 52, 69, 71, 82, 87, 95, 74, 55, 78, 49,
60),c(80,80,80, 80, 80, 80, 80, 80, 80, 80, 80, 80)))
Pearson's Chi-squared test
data: rbind(c(79, 52, 69, 71, 82, 87, 95, 74, 55, 78, 49, 60), c(80,
80, 80, 80, 80, 80, 80, 80, 80, 80, 80,
2007 Apr 17
3
Extracting approximate Wald test (Chisq) from coxph(..frailty)
Dear List,
How do I extract the approximate Wald test for the
frailty (in the following example 17.89 value)?
What about the P-values, other Chisq, DF, se(coef) and
se2? How can they be extracted?
######################################################>
kfitm1
Call:
coxph(formula = Surv(time, status) ~ age + sex +
disease + frailty(id,
dist = "gauss"), data = kidney)
2011 Jan 06
1
need help for chi-squared test
I've got a dataset which looks like this in the beginning:
cbr dust smoking expo
1 0 0.20 1 5
2 0 0.25 1 4
3 0 0.25 1 8
4 0 0.25 1 4
5 0 0.25 1 4
(till no. 1240, anyway, a huge set)
I have to analyse cbr and smoking, I know it works with chisq.test() for the
whole set, but I only need cbr and smoking, and I
2003 Mar 26
3
a statistic question about chisq.test()
Hi,
In the chisq.test(), if the expected frequency for some categories is <5, there will be a warning message which says
Warning message:
Chi-squared approximation may be incorrect in: chisq.test(x, p = probs)
I am wondering whether there are some methods to get rid of this mistake... Seems the ?chisq.test() doesn''t provide more
options to solve this problem. Or, the only choice is
2017 Dec 28
1
Numerical stability in chisq.test
> On 28 Dec 2017, at 13:08 , Kurt Hornik <Kurt.Hornik at wu.ac.at> wrote:
>
>>>>>> Jan Motl writes:
>
>> The chisq.test on line 57 contains following code:
>> STATISTIC <- sum(sort((x - E)^2/E, decreasing = TRUE))
>
> The preceding 2 lines seem relevant:
>
> ## Sorting before summing may look strange, but seems to be
>
2003 Dec 09
2
p-value from chisq.test working strangely on 1.8.1
Hello everybody,
I'm seeing some strange behavior on R 1.8.1 on Intel/Linux compiled
with gcc 3.2.2. The p-value calculated from the chisq.test function is
incorrect for some input values:
> chisq.test(matrix(c(0, 1, 1, 12555), 2, 2), simulate.p.value=TRUE)
Pearson's Chi-squared test with simulated p-value (based on 2000
replicates)
data: matrix(c(0, 1, 1,
2008 Nov 16
3
chisq.test with simulate.p.value=TRUE (PR#13292)
Full_Name: Reginaldo Constantino
Version: 2.8.0
OS: Ubuntu Hardy (32 bit, kernel 2.6.24)
Submission from: (NULL) (189.61.88.2)
For many tables, chisq.test with simulate.p.value=TRUE gives a p value that is
obviously incorrect and inversely proportional to the number of replicates:
> data(HairEyeColor)
> x <- margin.table(HairEyeColor, c(1, 2))
>