Linked Questions

55
votes
10answers
3k views

What are some examples of anachronistic practices in statistics?

I am referring to practices that still maintain their presence, even though the problems (usually computational) they were designed to cope with have been mostly solved. For example, Yates' ...
29
votes
4answers
51k views

Fisher's Exact Test in contingency tables larger than 2x2

I was taught to only apply Fisher's Exact Test in contingency tables that were 2x2. Questions: Did Fisher himself ever envision this test to be used in tables larger than 2x2 (I am aware of the tale ...
17
votes
2answers
4k views

Contingency tables: what tests to do and when?

I'd like to see an extension of this discussion of the age-old chi-sq vs. Fisher's exact test debate, broadening the scope a bit. There are many many tests for interactions in a contingency table, ...
9
votes
1answer
8k views

Alternatives for chi-squared test for independence for tables more than 2 x 2

What are some alternatives to the chi-squared test for categorical variables with tables larger than 2 x 2 and cells with a count less than 5, if I don't want to merge classes?
5
votes
3answers
6k views

For chi-square on any 2 by X contingency table, should no more than 20% of the cells be less than 5?

In their 1999 book, Yates, Moore & McCabe specify that no more than 20% of expected counts should be less than 5 and all individual expected counts should be greater than 1. Does this mean that, ...
4
votes
2answers
5k views

Chi Square Test for Independence in R and Python

Consider the following R code and output: ...
7
votes
2answers
2k views

Is the chi-squared test appropriate with many small counts in a 5x2 table?

I have two sample populations, A, and B, which are independent. ...
7
votes
1answer
10k views

R: prop.test - Chi-squared approximation may be incorrect

I am trying to compare the proportions of two populations, using prop.test My data is straightforward - first population is 6/26 and second is 15/171. I am trying ...
7
votes
1answer
5k views

Why do p values for test of likelihood ratio vs Fisher's Exact Test not agree

In a 2x2 analysis of categorical data, what causes the p value for the test of the likelihood ratio to differ from both the Fisher's Exact Test and the test of linear-by-linear Association? ...
5
votes
2answers
549 views

Chi-squared test: Investigating fruit flies attraction to different colours

I have a few questions about the Chi-squared test. First of all, this is what I was investigating: H0: Fruit flies show no difference in attraction to light of different colours Protocol: 20 fruit ...
3
votes
1answer
3k views

Post hoc chi-square test

I am looking at a $\chi^2$ (crosstabs) test looking at interactions between types of dyads in an animal group. My categories are Male-Male, Male-Female, and Female-Female dyads in the rows and "Were ...
2
votes
3answers
3k views

N-1 Pearson's Chi-Square in R

I have two categorical variables and was looking into doing a chi-square test. I then noticed I had some low frequencies in my contingency table and thought Fisher's Exact Test may be useful. I've now ...
8
votes
1answer
1k views

test if a markov chain is equal to a theoretical one

I have got an empirical transitions count matrix Q. I have a theoretical first order Markov chain P. Say N is the number of transitions. I would like to test if Q is compatible with P. Is it correct ...
2
votes
1answer
3k views

How to prove significantly high or low values?

I have the counts of genes in particular pathways from three organisms. How to statistically prove that few counts are significantly high or low as compared to another organism. My data looks like ...
5
votes
1answer
691 views

Using $\chi^2$ or Fisher's exact test with low expected counts

Let's say I have 7 urns filled with random numbers of colourful marbles. An example dataset is as below: ...

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