similar to: power 2x3 exact test

I'm using fisher.exact on a 4x2 table and it seems to work. Does anyone know exactly what is going on? I thought fisher.exact is only for 2x2 tables. Note: I can't use chi-squared because I have a couple of cells with 0 and < 5 observations. -- View this message in context: http://r.789695.n4.nabble.com/fisher-exact-for-2x2-table-tp3481979p3481979.html Sent from the R help

Hello everyone, I have a variable with several categories and I want to convert this into dummy variables and do logistic regression on it. I used model.matrix to create dummy variables but it always picked the smallest one as the reference. For example, model.matrix(~.,data=as.data.frame(letters[1:5])) will code 'a' as '0 0 0 0'. But I want to code another category as

Hi there, I have the following plot. The circles and the line do not cross in the main plot. But in the legend, the circle and the line cross. I am wondering if there is a way to make the legend look like the plot without crossing. I looked around but did not find a way to do that. Is it doable? plot(x,x^1.5, pch=1, lty=1, type='b') legend(1,25, legend="hello",pch=1,

Dear All, I have a problem understanding the difference between the outcome of a fisher exact test and a chi-square test (with simulated p.value). For some sample data (see below), fisher reports p=.02337. The normal chi-square test complains about "approximation may be incorrect", because there is a column with cells with very small values. I therefore tried the chi-square with

Hello, I am trying to find a permutation test that works on a general nxm table. The data set is small enough to have cells with too small counts to make chi2-approximation invalid. If the table was a 2x2 contingency table I would like to use a Fsher exact test (fisher.test) but that wont work in this general table. Does there exist a general function for this test. Best regards, Magnus

Warranty on Accuracy, Precision, Legality, ... of R in Research (These questions may well have been raised.) What is the implied warranty of using R for research & publications, consulting, etc.? Alternately, how does one obtain such a warranty? Your answers will be much appreciated. Perhaps you can point me to some websites which discussed this subject in the past. Thanks & regards

Hi All, My apologies if this is a totally newbie question. I want to calculate the probability that a particular set of genes is picked repeatedly for 3 samplings. For example, if from a total of 'N' genes, I pick 'A' number of genes in the first pick, 'B' number of genes in the second pick, and 'C' number of genes in the third pick, I would want to calculate

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

Appology in advance if this has been asked and answered. I am getting different answers using Fisher's exact test in the package ctest. For example: x_cbind(c(8, 22), c(31, 29)) fisher.test(x) Fisher's Exact Test for Count Data data: x p-value = 0.04024 alternative hypothesis: two.sided However, in SAS or other packages on the net the answer I get is p-value= 0.02664. Is this

I want to ascertain the basis of the table ranking, i.e. the meaning of "extreme", in Fisher's Exact Test as implemented in 'fisher.test', when applied to RxC tables which are larger than 2x2. One can summarise a strategy for the test as 1) For each table compatible with the margins of the observed table, compute the probability of this table conditional on the

Good Afternoon, My name is Gabriel, I'm doing an analysis if there is increase or decrease in dependence on the mutated genes, using 3 or more genes using the fisher exact test.I performed with success an analysis for two genes using fisher.test( ). example of the 2x2 contigency table: Gene A mutated | Gene A normalGene B mutated| 26

The hybrid feature in fisher.test looks to me like an excellent way to analyze my two-way tables. The only problem is that it does not seem to be implemented. Am I right about this? An example is pasted below. I note that I get the warning message only when I shouldn't: for a 2x2 table hybrid seems to be ignored without warning. In no case does fisher.test seem to be checking Cochran

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

i have 2 groups i want to compare: group A and group B each group contains let's say 20 patients i want to perform a Fisher Exact test on genotype distribution so, see if there is a sign diff in genotpe frequency/distribution (#AA, #AB, #BB) between group A and B not for 1, but for 1000 different genes my question: how should i build my table so i can do: test <-

Hello all, I would like to know what the difference is between chisq.test and fisher.test when using the Monte Carlo method with simulate.p.value=TRUE? Thank you -- View this message in context: http://r.789695.n4.nabble.com/Difference-in-Monte-Carlo-calculation-between-chisq-test-and-fisher-test-tp2322494p2322494.html Sent from the R help mailing list archive at Nabble.com.

Hi All. Sorry to bother you. I have a question about fisher exact test. I counted the presence of gene mutation in two groups of samples. My data is as follows Presence Absence GroupA 4 6 GroupB 5 11 When using the formula of fisher exact test provided by wiki (http://en.wikipedia.org/wiki/Fisher%27s_exact_test), the p-value is 0.29. But when

I posted this last night but I think I figured out the problem. I checked on the underlying equation for the Fisher Exact Test for tables greater than 2X2. It looks like I have an insane amount of factorials to be multiplied. Is that problem? Is it an overflow issue? Jeff Last night’s post: I just a ran a fisher.test on a 9x5 table and received the following message

In an effort to select the most appropriate number of clusters in a mixture analysis I am comparing the expected and actual membership of individuals in various clusters using the Fisher?s exact test. I aim for the model with the lowest possible p-value, but I frequently get p-values below 2.2e-16 and therefore does not get exact p-values with standard Fisher?s exact tests in R. Does anybody know

Hi folks, Forgive me if this question is a trivial issue. I was doing a series of Fishers' exact test using the fisher.test function in stats package. Since the counts I have were quite large (c(64, 3070, 2868, 4961135)), R suggested me to use *other algorithms* for the test which can be specified through the 'control' argument of the fisher.test function as I understood. But where

Hi I was wondering whether anyone can help me with this problem....it's been driving me nuts, I've been trying to figure it out for months and months without success!! Basically I have a group of participants who attended 2 experimental sessions a few months apart. I took measures of the way they approach two tasks at Time 1 and the same two tasks at Time 2. I have categorical data (a