Displaying 20 results from an estimated 655 matches for "chisqs".
Did you mean:
chisq
2012 Jun 26
5
chisq.test
Dear list!
I would like to calculate "chisq.test" on simple data set with 70 observations, but the output is ''Warning message:''
Warning message:
In chisq.test(tabele) : Chi-squared approximation may be incorrect
Here is an example:
tabele <- matrix(c(11, 3, 3, 18, 3, 6, 5, 21), ncol = 4, byrow = TRUE)
dimnames(tabela) <- list(
2005 Oct 20
3
numerical issues in chisq.test(simulate=TRUE) (PR#8224)
Hi,
This report deals with p-values coming from chisq.test using
the simulate.p=TRUE option. The issue is numerical accuracy
and was brought up in previous bug reports 3486 and 3896.
The bug was considered fixed but apparently was only mostly
fixed. Just the typical problem of two values that are
mathematically equal not ending up numerically equivalent.
Consider this series of three 2x2
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))
>
2005 Jun 22
1
chisq test and fisher exact test
Hi,
I have a text mining project and currently I am working on feature
generation/selection part.
My plan is selecting a set of words or word combinations which have
better discriminant capability than other words in telling the group
id's (2 classes in this case) for a dataset which has 2,000,000
documents.
One approach is using "contrast-set association rule mining" while the
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
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
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,
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
>
2008 Feb 14
0
help in simplyfiying programme
my program given below can some one make it presentable. I trying to simulate survival data and calculate the power. I think i could have done better.
s=10
number=0
count1=0;count2=0;count3=0;count4=0;count5=0;count6=0;count7=0;count8=0;
count9=0;
count11=0;count22=0;count33=0;count44=0;count55=0;count66=0;count77=0;
count88=0;count99=0;
while(s!=0){
n=100
n1=n/2
n2=n/4
2003 Jul 15
0
Why two chisq.test p values differ when the contingency
Hi Tao:
The P-values for 2x2 table are generated based on a random (discrete
uniform distribution) sampling of all possible 2x2 tables, conditioning
on the observed margin totals. If one of the cells is extremely small,
as in your case, you get a big difference in P-values. Suppose, you
changed the cell with value 1 to, say, 5 or 6, then the two P-values
are nearly the same. However, I
2002 Jul 30
4
chisq.test, basic question
The cells are interpreted as counts, so by scaling you're analyzing a
different experiment (one with fewer observations). So the chi-squared value
will change (the terms (O-E)^2/E in the statistic scale linearly ignoring
rounding and "Yates' continuity correction").
The chisq.test on the original data is a test of association. Conventionally
you decide ahead of time on a
2014 May 07
3
historical significance of Pr(>Chisq) < 2.2e-16
Where does the value 2.2e-16 come from in p-values for chisq tests such
as those
reported below?
> Anova(cm.mod2)
Analysis of Deviance Table (Type II tests)
Response: Freq
LR Chisq Df Pr(>Chisq)
B 11026.2 1 < 2.2e-16 ***
W 7037.5 1 < 2.2e-16 ***
Age 886.6 8 < 2.2e-16 ***
B:W 3025.2 1 < 2.2e-16 ***
B:Age 1130.4 8 < 2.2e-16 ***
W:Age 332.9 8 < 2.2e-16 ***
---
Signif.
2008 Jan 17
1
'simulate.p.value' for goodness of fit
R Help on 'chisq.test' states that
"if 'simulate.p.value' is 'TRUE', the p-value is computed by Monte
Carlo simulation with 'B' replicates.
In the contingency table case this is done by random sampling from
the set of all contingency tables with given marginals, and works
only if the marginals are positive...
In the
2005 Jun 26
2
chisq.test using amalgamation automatically (possible ?!?)
Dear List,
If any of observed and/or expected data has less than
5 frequencies, then chisq.test (Pearson's Chi-squared
Test for Count Data from package:stats) gives warning
messages. For example,
x<-c(10, 14, 10, 11, 11, 7, 8, 4, 1, 4, 4, 2, 1, 1, 2,
1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1)
y<-c(9.13112391745095, 13.1626482033341,
12.6623267638188, 11.0130706413029, 9.16415925139016,
2003 Jul 16
1
The two chisq.test p values differ when the contingency table is transposed! (PR#3486)
Full_Name: Tao Shi
Version: 1.7.0
OS: Windows XP Professional
Submission from: (NULL) (149.142.163.65)
> x
[,1] [,2]
[1,] 149 151
[2,] 1 8
> c2x<-chisq.test(x, simulate.p.value=T, B=100000)$p.value
> for(i in (1:20)){c2x<-c(c2x,chisq.test(x,
simulate.p.value=T,B=100000)$p.value)}
> c2tx<-chisq.test(t(x), simulate.p.value=T, B=100000)$p.value
> for(i in
2005 Oct 20
3
different F test in drop1 and anova
Hi,
I was wondering why anova() and drop1() give different tail
probabilities for F tests.
I guess overdispersion is calculated differently in the following
example, but why?
Thanks for any advice,
Tom
For example:
> x<-c(2,3,4,5,6)
> y<-c(0,1,0,0,1)
> b1<-glm(y~x,binomial)
> b2<-glm(y~1,binomial)
> drop1(b1,test="F")
Single term deletions
Model:
y ~
2003 Jul 15
1
Why two chisq.test p values differ when the contingency table is transposed?
I'm using R1.7.0 runing with Win XP. Thanks,
...Tao
????????????????????????????????????????????????????????
>x
[,1] [,2]
[1,] 149 151
[2,] 1 8
>t(x)
[,1] [,2]
[1,] 149 1
[2,] 151 8
>chisq.test(x, simulate.p.value=T, B=100000)
Pearson's Chi-squared test with simulated p-value (based on 1e+05
replicates)
data: x
X-squared = 5.2001, df =
2008 Jan 08
1
A question on chisq.test
Dear all,
I would like to do a goodness-of-fit test on my data to see if they follow a mixture of 2 poisson distributions. I have small numbers for observed values. Most of them <5. The chisq.test gives warning message: Chi-squared approximation may be incorrect in: chisq.test(x , p = prob). However, the option sim=TURE would suppress the warning message. Does that mean with the option
2008 Feb 07
3
how to calculate chisq value in R
for example, an expression such as chisq(df=1,ncp=0) ?
thanks
--
View this message in context: http://www.nabble.com/how-to-calculate-chisq-value-in-R-tp15338943p15338943.html
Sent from the R help mailing list archive at Nabble.com.
2009 May 09
2
need help with chisq
I am very new to R. I have some data from a CVS stored in vdata with 4
columns labeled:
X08, Y08, X09, Y09.
I have created two new "columns" like so:
Z08 <- (vdata$X08-vdata$Y08)
Z09 <- (vdata$X09-vdata$Y09)
I would like to use chisq.test for each "row" and output the p-value
for each in a stored variable. I don't know how to do it. Can you
help?
so far I have