Questions tagged [fishers-exact-test]

A hypothesis test for contingency tables.

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How do I combine two groups into one for Fisher's Exact test?

I'm fairly new to statistics and I need some help. I just ran a survey on colour terms in different languages. I had 3 groups with an unequal number of participants in each: English (27), Scottish ...
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Fisher's Exact Test for 4 subgroups

I have a question for using Fisher's exact test for subgroups. I have 39 subjects that was divided into 4 groups( n = 9, 5, 10, 15, respectively). There were 3 conditions dividing the groups. Table ...
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Pvalue comparison at group or level

I am looking at pvalue. 2 groups x 4 levels. I ran a fishers exact test and got a pvalue. Does that pvalue relate to the group comparison as a whole or to a comparison of each individual level? Can I ...
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Choosing statistical test for Preference-shift

I am having trouble choosing the proper method to support my hypothesis. I have conducted an animal study, where subjects chose A or B, 6 times a day for 3 days (day 1~3). At first, I divided the ...
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Binomial test with Chance level prediction

Thanks for reading. I wanted to ask if my logic I used for my experiment makes any sense. My hypothesis is that watching Pepsi commercial increases Pepsi preference. My experiment has 2 steps. (1) ...
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How to test if watching a advertisement only 1 time is enough to change one's preference

I'm sort of having a trouble finding what statistical test to use in a specific project of mine. My experiment was as follows: I have 10 friends and they all prefer Coke cola then Pepsi. Each of them ...
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Hypothesis testing for ordinal proportions for multiple independent subjects divided between two groups

I have two biological groups - each with multiple subjects (7 in one and 10 in another). Each subject provides 40-80 observations, which can be classified into either of two ordinal categories. I have ...
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Using svychisq with complex survey tables that have one or more cells with null values

Does anyone more experienced with R's survey package know about an alternative for svychisq for the case of a contingency table with at least one cell with a zero value? There does not seem to exist ...
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Multinomial with small counts and many cells

I have data distributed as multinomial, with $N= 1,000$ observations divided among $n=10,000$ cells, with unequal probabilities $p_i$, for $i=1,...,n$. I would like to assess how likely it is that an ...
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Fisher's exact test with altered null hypothesis/expected frequencies

I'm trying to determine whether or not exposure to extreme temperatures after hospital discharge affects the chance that a surgical patient will be readmitted. An extreme heat exposure is defined as a ...
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Testing the difference of proportions equal to a certain value

Suppose there are two samples $X_1\dots X_n$, $Y_1\dots Y_m$ of binary variables $X\sim Bern(p_1)$ and $Y\sim Bern(p_2)$. Is there any way to test the following hypothesis by the exact test? $$H_0: ...
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When to correct for multiple comparisons when using fisher exact test?

Please, I'm just confused about whether to use a correction of multiple comparisons of the p values that I got from fisher exact test or not?. The data that I have is something like this: ...
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The use of Fisher's Exact test for Cougar (Puma concolor) Injury in the United States

In 2019 a research paper was published measuring the association between cougar attacks on humans using the Fisher's Exact test between 1924 to 2018 [1]. There were a total of 74 attacks reported from ...
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Careful comparison of strength of evidence (p-values)

Please hear me out before you roll your eyes when reading about "p-value comparisons". I have the following scenario: High-dimensional, clustered data and two groups within each cluster. ...
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Do poisson regression and exact poisson regression only differ in confidence interval?

The point estimates from the two approaches are the same, right? I plan to use exact Poisson regression for a study, since the events could be sparse after adjusting for a few covariates. Is there ...
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Test for statistical significance between groups in categorical count data with multiple samples

There are two groups/genotypes of mice (WT, KO). For each genotype, four mice were separately used to determine the identities of thousands of individual cells from a particular organ, assigning them ...
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Fisher's exact test in more than 2 variables

I have some data with three independent categorical variables (one has a sense of order, the others do not) and one dependent categorical variable. Is there an analogue to Fisher's exact test where I ...
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Hypothesis testing: Fisher's exact test and Binomial test

My first post in this community. My knowledge of statistics is limited, and so I am seeking advice on the following problem. (Sorry for the long post, and thank you in advance for your help). I have a ...
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Significance Testing for the Difference between Binomials [duplicate]

I have two algorithms, $A_1$ and $A_2$. $A_1$ either accepts or rejects samples from dataset $P$ $A_2$ either accepts or rejects samples from dataset $Q$ Below is a 2x2 contingency table for the ...
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Can I use fisher test on a $1 \times n$ table for comparing multiple proportions?

Let $X$ be $1$ (success) if some event occurs and $0$ other wise, let $p_i$ be the proportion of successes in the population $i$, so I'd like to use fisher exact test to test: $H_0: p_i=p_j$ for all $...
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Interpreting results from correlation, Fisher and regression [closed]

I am currently analyzing a data frame of two variables, power and time. Both are in discrete intervalls, power is given in natural numbers (including 0), time is given in days (format yyyy-mm-dd). All ...
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The use of Fisher's test to find associations in a categorical sequence

I have a sequence of categorical variables, each number represents a category. Some events in the sequence are "clustered". Here is a dummy example (clustered events are separated with "...
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Hypothesis Testing on Derived Distributions

Suppose we have access to samples from two probability distributions $P$ and $Q$ which may be arbitrary and high dimensional but are over the same domain $\mathbb{X}$ (for example $P$ and $Q$ may be ...
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Compute p-value in a contingency table other than 2x2 table

I guess I have a newby question here. I have used the tableone R package to create the contingency table shown below. I am struggling to understand which test was used by the package to compute the p-...
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Interpretation of Odds Ratio (OR) in Fisher's exact test [duplicate]

I've tried using R operating Fisher's exact test to test for independence of the 2 datasets below and struggling to interpret the Fisher report. Please have a look at the data and the Fisher's test ...
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Interpretation of Odds Ratio (OR) in Fisher's exact test

I've tried using R operating Fisher's exact test to test for independence of the 2 datasets below and struggling to interpret the Fisher report. Please have a look at the data and the Fisher's test ...
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How to measure the strength of association between two variables where majority of pair are assosiated?

I am quite new to the stat so facing a huge problem in result extraction, I have a large dataset running ~19000 (genes) x1500 (patients). I would like to see the dependence between two variables (one ...
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R and C categories relatedness Fisher exact test

I am trying to compare a symptom expression with identified pathogens in plants. I cant use the chi-square test as I have a sample with a low count. And I am not sure about Fisher exact test if it is ...
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Fisher Exact test - Can't replicate SPSS results in Excel

I've been doing some Fisher Exact tests in SPSS and am trying to do in Excel instead. So i can do automatically for rows of data. But I can't get the Excel results to match the results from SPSS. The ...
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Fisher exact test (in R) gives significant p-value but confidence interval spans 1 [duplicate]

Below is the reproducible data that can run from R using the base packages. ...
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Percent chance that two samples are different population (NPS)

Practical question (not a statistician), I want to make a PPT slide (amongst several) in a business discussion, related to comparing a new survey with an old one. Want to be able to say something to ...
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Alternative to Fisher's exact test when observations are not independent

I have a situation where I was planning to use post-hoc Fisher's exact tests to look for significant differences in the ratios of populations of cell subsets in response to treatments, but I'm ...
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Calculate sample size for Fisher Exact Test

I'm researching the role of sender reputation in remediating Android vulnerabilities using large-scale notification campaign. There are 2 senders with different reputations and 1 as a control (no ...
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Which Statistical Hypothesis Test is appropriate Here?

I have two contingency tables (screenshots below) - This is the results of age range 19-30, I also have two tables for above 30s. I am requesting help with rejecting a null hypothesis. The data was ...
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Fisher's Exact Test for 2x2 Table with Random Zero

I'm trying to determine if the rate of mutation for a particular gene is significantly different between two groups (primary tumor and metastases) with Fisher's exact test and so my contingency table ...
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fisher.exact test not returning expected p-value [duplicate]

I am trying to run Fisher Exact Test, however, I get unexpected results. I thought the two.sided p-value should be twice as large than the minimal one-sided p-value....
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Freeman Halton Long hand

I am looking at this site: https://www.danielsoper.com/statcalc/formulas.aspx?id=58 Where for a 2x3 table it gives the following formula: The calculator equivalent (https://www.danielsoper.com/...
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Freeman-halton simple examples?

Does anyone know where I can see a step by step simple example of the Fisher-Freeman-Halton equation? I am a developer so need to build the process from scratch and have already done so for the Fisher ...
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How is fishers exact test calculated for non mathematician

I am referring to the Wikipedia example here (https://en.wikipedia.org/wiki/Fisher%27s_exact_test) which shows: My Question is how is this 0.001346 figure reached? After reading, I appreciate that ...
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2 votes
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Boschloo or Barnard? In which case?

For 2x2 contingency tables, my understanding is that Boschloo and Barnard both have uniformly more power than Fisher's exact test (even if all marginals are fixed??). But I am still confused about the ...
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Fisher exact test manual input of observed and expected

I have a 4x4 table and I want to test if observed proportion equal to a given expected proportion I provide. Because the counts between observed and expected are very different, I am interested in ...
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Comparing multiple sample proportions between two groups where one group is a subset of the other

I have 2 populations which I want to test if the proportions between group A and B are the same for each location or not by using hypothesis testing. It's very much as this problem described here: ...
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p-value from fisher.test() does not match phyper() in R?

My question was inspired by this topic, but is a bit different: phyher() in R and Fisher exact test p-value I try to understand how does it work? The question is as follows: knowing that 50 people out ...
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1 answer
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How to use permutation test to find significant outcomes from many fisher exact tests

I am reading from this where they mention running 500K fisher exact test to find significant associations between different DNA changes and a phenotype. They also mention that Bonferroni, Benjamini, ...
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Chi Square Test on small sample size

I have the following dataset and I am trying to run a Chi-square test between the control and pilot. The only issue is that, for a Chi-Square test to return proper results, the sample size need to be ...
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Establish confidence / error for multiple contingency tables with dynamic outcomes

In a task, a participant sees two types of prompts, 1 and 2. The participant might answer A or B. The participant might give an answer that cannot be coded as A or B, we treat these as missing data. ...
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Use of Chi-Square test of independence / Fisher Exact Test?

One of my research hypotheses is that individuals from Southeast Asia who are ethnically Chinese are more likely to experience racially motivated hate crimes than their counterparts from other ethnic ...
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Post hoc test for Fisher's exact test (larger than 2x2)?

I have 2 categorical variables: Var1 - 3 levels, Var2- 5 levels (i.e., table is bigger than 2x2). I'm using SAS, and since I have multiple cells <5, I have run a Fisher's exact test with Monte ...
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1 vote
1 answer
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Sample size for binary outcome with rare events

I want to compute the sample size to compare two groups for a binary outcome where we expect rare events. I will do an example with R. Assume the following expected probabilities of observing an event ...
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1 vote
1 answer
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Comparing multiple sample proportions between two groups

Hi all and thanks for taking the time to read this question. I'll try to be as clear as possible! The data: I have one sample of patients which was divided in two groups based on a binary variable for ...
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