Tables of counts (occasionally proportions of marginal counts), arranged by (at least) two marginal categories, displaying bivariate or multivariate frequencies. Sometimes called crosstabs.

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28 views

why are the degrees of freedom for a chi-square test on a 2x2 contigency table always 1?

I know the "formula" is (# rows - 1) * (# columns -1). However, shouldn't the design of the experiment or observational study being conducted make a difference? The only experimental design I can ...
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4 views

Preprocessing contingency table

I'm going to apply a correspondence analysis on some datas. I'm having doubts on preprocessing the contingency table: my dataset contains informations on salaries and problems in different spanish ...
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4 views

Comparing set of counts with different n sample and many zeros.

I had a look of may treats and find different pieces here and there but I cant figure out how to do this "simple" comparison. I have 2 counts (obtained with different methods but assuming from same ...
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28 views

Hypothesis testing for difference in proportions when pooled population proportion is known

The example I use below to frame my questions is a bit contrived, but I am hoping the answer will help to clarify my understanding of more complex, related issues. Suppose we know in advance that the ...
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0answers
41 views

Chi square test in a contigency table with sampling zeroes

im trying to estimate if an association exists between two variables in a 7x5 contingency table (the type of prosthesis with the type of complication). The table contains a lot of sampling zeroes and ...
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2answers
54 views

How to proceed with chi square test in R if one line has zeros?

I am trying to program with R. My categorical data is in a table of 5*5. However, the 5th line has only zeros. When I run the chi square test in a software program, it returns the result INVALID. But ...
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1answer
27 views

Fisher and chi-squared assumptions/limitations not met

Fisher exact test is said to be used with a total sample (n) < 1000, whereas chi-squared test should be used when each category (/cell in a contingency table) >=5. What if you have an mxn ...
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21 views

Effect size measure for mxn Fisher Exact Test

I'm using the R function to run fisher exact test for mxn contingency tables (since my sample size <5; limitation of the chi-squared test). Along with the p-value I want to state the effect size. ...
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1answer
16 views

Show that the adjusted values for 2x2 tables under the assumption of independence have the same absolute value

I am trying to show that, for 2x2 tables, under the assumption of independence, that all four adjusted residuals have the same absolute value. Adjusted residual: $r_{ij}=\dfrac{n_{ij}-\hat{u_{ij}}}{\...
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14 views

Why is homogeneous association symmetric

Could someone please explain to me why homogeneous association (say in a $2\times 2\times k$ table) is a symmetric property? As in why does homogeneous association between X and Y given Z mean there ...
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30 views

should the product of 2 independent binomials converge to a normal distribution for large sample sizes?

I have been studying 2x2 contingency tables and specifically I have been looking at situations where the marginals are fixed by design for one categorical variable. As an example, suppose a ...
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1answer
16 views

Using R: I want to create a contingency table with a 4 category variable [closed]

Currently I have data on SEX and outcome. For outcome there are 4 different values possible 1, 2, 3, 4. I want to create a contingency table (so that I can eventually do a Fisher test) such that I ...
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18 views

Fisher exact test with permutations to measure enrichment

I am looking at enrichment of a specific genomic feature within specific blocks in the genome. Based on simply the number/size of features and the genome blocks there is enrichment, but neither ...
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0answers
15 views

Poisson regression residual analysis

In a three factor poisson (log-linear) model $(A*B*C)$, when the highest interaction term $(A:B:C)$ is dropped, the response/raw residuals are exactly the same for different levels of two of the ...
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1answer
28 views

Measure heterogeneity among multiple samples and scale variables

I would like to know what are the available statistical measures for quantifying heterogeneity on data that look like this... ...
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0answers
18 views

Mutations in known DNA sequence: which test to use?

I am analysing a double knockout (mouse), and trying to see whether restoring one or another of the genes it's missing affects specific positions preferentially in a third gene. The data* looks ...
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0answers
27 views

Comparing classifier with random classifier. Imbalanced data with small sample.

I would like to compare a classifier I developed against a random classifier. However, I have only 82 testing samples with 12 (15%) positive cases. I am planning to use McNemar's test. The way I ...
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0answers
14 views

Sample size to determine correlation between multiple binomial variables?

How can I calculate the sample size to test for a correlation (p < alpha) between multiple (k > 2) binomial variables, where the frequency f of each variable is very low? For example, what sample ...
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0answers
34 views

Barnard's Exact Test (Boschloo's variant) when distribution is hypergeometric

Let's say, we have a standard $2 \times 2$ contingency table and because of low sample size we're about to use some type of Exact Test, e.g. Fisher's Exact Test (FET) or Barnard's Exact Test. It's ...
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0answers
23 views

Equation for marginal odds ratio

I am working my way through Alan Agresti's "Categorical Data Analysis and I am stuck at a seemingly very simple exercise. This is about a 2x2x2 contingency table. The notation used is as follows: ...
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1answer
31 views

Statistical analysis of fourier transform of a 2D image (freaking AMAZING)

I'm a statistics grad student, and I just started getting into Digital-Image-Processing (an analogy for processing super-large contingency tables). In the book "Digital Image Processing" by Gonzalez ...
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0answers
14 views

Conditional probability of contributing to the (1,1) cell of a 2-by-2 table, given the row and column sums

Suppose you have data from a 2-by-2 table \begin{array}{c|cc} {\rm } & {\rm Yes} & {\rm No} \\ \hline {\rm Yes} & N_{11} & N_{10} \\ {\rm No} & N_{01} & N_{00} \\ \...
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0answers
82 views

Statistical test for paired data in an r x c contingency table

To perform statistical test on paired data when we have two dichotomous nominal variables (i.e., in a 2 x 2 contingency table) we can use the McNemar's test. When ...
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0answers
12 views

How does *structural* symmetry effect the analysis of square contingency tables?

I am working with a contingency table new to genetics called a "Hi-C Dataset," which in it's simplest (and maybe not most articulate) sense represents counts of co-occurence in 3D SPACE of disparate ...
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27 views

Sample Size in a multiway contingency table

I am planning a trial involving sterilizing biological material with four treatments (1 Rinse and 15% solution strength, 1 Rinse and 25% solution strength, 2 rinse and 15% solution strength, 2 rinse ...
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26 views

Dealing with sampling zeros

I would like to perform a $\chi^2$-test, but due to low sample size in some cases, I have sampling zeros. One example of such a case: ...
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0answers
50 views

P values and calculating residuals in chi-squared contingency tables

Given an n x m contingency table I calculate a chi-squared value and probability for that table telling me if there are cells that differ significantly from the mean. I go to calculate the adjusted ...
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1answer
51 views

How to calculate mutual information from frequencies

Can someone explain to me how to calculate mutual information from contingency table? I have a contingency table containing counts from a sample of data And I want to calculate the mutual ...
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0answers
23 views

Comparison between two conditions

I want to compare the effects of a treatment with placebo. The values are the number of subjects that reach a particular level of pain threshold. Since the values in before and after are dependent ...
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0answers
23 views

How to calculate Wald Chi-squared test for contingency table

I am trying to understand the documentation from SAS concerning the Wald Chi-squared test for contingency tables via the surveyfreq procedure. Specifically, I am ...
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0answers
25 views

How do I create a four-way contingency table in R? [closed]

I’m doing interaction analysis and am trying to figure out how to set up the variables so I get the structures I’ll need in R. Not sure where to start, as most contingency table examples are VERY ...
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1answer
73 views

Residuals colors of the mosaic plot are all dark. Implies?

I am working on interpreting the nature of the association of a contingency table. I tried to provide a mosaic plot of the data that I have and it resulted to Can anyone help me interpret this data ...
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2answers
218 views

SciPy chisquare applied on continuous data?

chi2 seems to be used to compare distributions between categorical features. Is it possible to use SciPy chisquare function to compare two distributions of continuous data ? For example : ...
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0answers
19 views

How collapsing columns in contingency tables influences independence of observations

Suppose we've got a table of frequencies of different transcripts in two samples of different tissue. For each transcript I want to perform a between-sample pairwise frequency difference test and ...
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2answers
77 views

Is there an r package similar to LEM for analyzing contingency tables? [closed]

Is there an R package for log-linear analysis that is similar to LEM? Here is an example LEM script ...
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0answers
46 views

Exact test for m x n contingency table conditional (i.e. fixed by design) on one margin

I have a $m \times n$ contingency table (with $m, n > 2)$ . The experiment yields ~15% cells with expected frequencies lower 5 and also zero counts in the empirical data. The prerequisite for the ...
2
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0answers
57 views

Fisher's exact test vs kappa analysis

I was reading a paper where the authors assessed the association between two different diagnostics tests intended to diagnose the same disease and they performed the analysis with Fisher's exact test. ...
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0answers
46 views

How to test the independence of two categorical variables with repeated observations?

I'm wondering how to test whether male and female birds differed significantly on the preference of habitat type on the following contingency table. ...
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0answers
162 views

Interpretation of global test (p-value) of the interaction term with two categorical variables, each has 3 levels, in Logistic regression

My data: I have a dichotomous outcome: Disease(Y/N); and 2 categorical independent variables, each has 3 levels -- IPV: 0 (ref), 1, 2 -- Race: White (ref), Black, Hispanic My research question: ...
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0answers
35 views

Calculating degrees of freedom for a contingency table with interactions

Below is a contingency table with residual deviance given by a Poisson regression model with a log-link. I have searched online and I believe that for the mutually exclusive model ...
3
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1answer
203 views

Logistic regression vs chi-square in a 2x2 and Ix2 (single factor - binary response) contingency tables?

I'm trying to understand the use of logistic regression in 2x2 and Ix2 contingency tables. For instance, using this as an example What is the difference between using chi-square test and using ...
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0answers
34 views

Is chi-squared for homogeneity right here?

The hospital I work for sends out a patient satisfaction survey after discharge (assuming a random independent draw of patients getting the survey), all multiple choice/categorical questions. Some of ...
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0answers
27 views

Chi square test for independence

While testing using contingency tables the hypothesis used are Ho: the two categorical variables are independent or not related H1: the variables are related. Suppose if Ho is rejected, can anything ...
4
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1answer
117 views

How to analyze $ 2\times n$ contingency table?

I have a $2\times n$ contingency table. I want to assess whether the rows are independent from the columns or not. If not, I want to know which columns are not independent and which are. What tests ...
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0answers
16 views

MLE's of Log-linear parameters

Can the MLE's of the log-linear parameters (the constant, main effects and the interaction effects) be infinite even if cell counts and the margins in a contingency table are all positive ?
2
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1answer
141 views

Analyzing multiple dependent pairs of 2x2 contingency tables

In advance, I ask forgiveness for my statistical naïvety. Suppose I have experimental data from pre- and post-treatment, and this data is split according to two binary categories like so: \begin{...
0
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0answers
52 views

Poisson distribution vs Three-way table to Compare multiple incidences

I need some help understanding the difference between comparing incidences of rare events with a Poisson distribution and using a three-way contingency table. I'm sure I have some fundamental ...
2
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0answers
43 views

Measure dependence of categorical and ordinal variable

My purpose: When trying to find out which variables of a generic questionnaire data set will show striking differences across columns in crosstabs, I first do correlation tests (or dependence tests) ...
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3answers
779 views

Chi-Square-Test: Why is the chi-squared test a one-tailed test? [duplicate]

In my Masters thesis I conducted an experiment in that subjects should decide between two alternatives. I had a control and a treatment group. The hypothesis was that in the treatment group more ...
4
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1answer
338 views

Boschloo or Barnard? Which Test for Cross Table Analysis?

Actually I am analyzing a 2x2 table from a small dataset of 30 patients. We are retrospectively trying to find some variables that give a hint about which treatment to choose. The variables (obs ...