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Re: nominal scale - comparison of populations
Posted:
Dec 23, 2012 6:47 PM
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<czytaczgrup@gmail.com> wrote in message news:49a8c832-2239-487d-85dd-c93bb8ad1932@googlegroups.com... Hi,
Using a short questionnaire I have interviewed two populations. For majority of questions the answers are of the nominal type only (there are more than two possible answers which are self excluding and complete). Now, I would like to check if these populations are/are not the same with respect to the frequencies given to answers. Therefore, the every possible answer was coded as a distinct integer number. This gives me a probability distribution. Can I use statistical tests to compare these distributions? If yes - would be the outcome of a test robust to the way in which the numbers are adjusted?
--------------------------------------------------------------------------------------------------------- I really have no business commenting here, I am merely an introductory level tutor. but your question might be elementary -- you have categorical data such as (to take an example using automobiles) color, style, etc. For data encoding purposes you may designate blue = 1, red =2, white = 3, etc. But to treat this data as a single variable with ordinal or cardinal rank is absurd. In what sense would white be 50% more than red and three times blue, or even white > red > blue ? OK, you didn't mention rank, so presumably you are aware of that.
Next, you can deal with proportions -- are there differences in colors among different body stayles? I would attack such questions using chi-square methods or perhaps ANOVA. Look up "test of homogeneity" in a standard stats text, for example. Does that help?
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