Jen Zhen wrote:
I have a summary table with members from (1) the treatment group and
(2) the control group of an experiment, and would like to provide for
each observable variable a formal test for whether the two sets of
people come indeed from the same population. For the continuous normal
variables, I am just doing a t-test to test for equality of means, but
I'm not fully sure what to do instead for the categorical variables
(with more than 2 categories).
I found the -csgof- command for a Chi-Square test of whether the
proportions of the different categories in one sample correspond to
those coming from some hypothesis, but which command would you use to
test whether the proportions in the two groups are identical?
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If your categories are nominal, then I second Nick Cox's recommendation. If
your categories are ordered, then -ranksum- would be a better bet. Either way,
you're going to need to convert proportions in each category in each group into
counts (tallies) in each category in each group, so you'll need to multiply the
proportions by the group sample sizes.
Joseph Coveney
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