I would like to test if there is an association between:

-A binary factor: 0, 1 (recovered vs not recovered) -A ordered factor: Iron level 1, 2, 3 (low, medium, high)

I was wondering if the rank of the iron level variables is considered, when testing for an association between those two variables using a Chi-Square test?



1 Answer 1


No, I don't think so. 1, 2, 3 are treated pretty much like unordered labels like "red", "green", "blue".

  • $\begingroup$ Thank you! Argh, I was worried it wouldn't, as the p-value is exactly the same when I tested the iron level as nominal factor. Do you have advice about which test I could use to test the association between an ordered factor and a binary categorical variable as in the example above? $\endgroup$
    – evouk
    Aug 14, 2019 at 11:30
  • 1
    $\begingroup$ A chi-square test surely is an option (would work even if the variable is ordered). You could treat the ordinal values as continuous and do the t-test to see if the mean is different between recovered vs not-recovered. Of course, this isn't really treating this variable as ordinal though. And this is a deep area. Have a look like this researchgate.net/post/… $\endgroup$
    – Kota Mori
    Aug 14, 2019 at 11:44
  • $\begingroup$ Thank you, that's really helpful. I think I'll take your advice and do a t-test to see if there is a significant difference in the means. $\endgroup$
    – evouk
    Aug 14, 2019 at 13:28

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