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Bayesian chi-square test

edited January 5

Hello,

I have a few questions regarding the Bayesian chi-square test. Namely, I want to conduct a chi-square test of homogeneity (using the contingency tables option), comparing 10 groups (countries) on one yes/no variable = a 10x2 contingency table. What I need is an omnibus test of differences between these 10 countries, to see if any of them is different from the others when it comes to the yes/no variable.

I read the latest JASP manual for this and found it very helpful, however, I wasn't entirely sure which sampling scheme to select when conducting the analysis. The data collection was conducted separately in each of the 10 countries, and we determined in advance how many participants we would recruit at minimum in each country (for the purposes of another analysis), however, this was not a strict stopping criterion and in some countries the data collection continued for as long as it could time-wise. Therefore, I was not sure whether independent multinomial sampling (as it is defined in the manual) fully applies here, as we did not precisely fix the country sample sizes in advance, but rather just set a minimum for each (and most countries ended up having sample sizes larger than this minimum). However, I don't think Poisson sampling applies either, as we did have this within-country approach and didn't just collect data as an overall dataset for as long as we could. Could you please help me in determining this?

My second question is whether this 10x2 contingency table is suitable for analysis with the current version of JASP. Namely, when I try to run the test (with the hypothesis that group 1 is not equal to group 2), I get a Bayes factor but with a note under the table saying that the "proportion test is restricted to 2x2 tables". Is the analysis I want to conduct (see first paragraph) possible in JASP given that there are ten groups, and the hypothesis only allows specifying relationships between "group 1 and group 2"?

Mirna

• Hi Mirna,

1. Definitely the independent multinomial, as you already suggested.
2. Yes, this test should work in JASP. I'm not sure about that note -- can you send an example csv and .jasp file?

E.J.

• Hi E.J.,

Thank you for the response!

As the .jasp file is too large to share here, I included it and an example of my data in this folder: https://drive.google.com/drive/folders/1_hyJFx96fZmkoxdsK3VGxtYLyeWsdtro?usp=sharing

(The data in the csv are randomly generated, but the categories of variables mirror those in the real dataset.)

Mirna

• Hi,

I have an additional question regarding the "prior concentration" option in the Bayesian chi-square window. I read the Jamil et al. (2016) paper as suggested in other comments on the forum, but still do not fully understand this concept. Could you please help me in understanding how this affects the analysis, and how I can determine the appropriate setting for my purposes?

Moreover, since I want to conduct 20 of these Bayesian chi-square tests (comparing the countries on 20 different yes/no variables), is it possible/necessary to correct for this large number of tests?