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Hello,
I'm trying to do a permutation test in Stata and just can't seem to
get the syntax right. Here's my command:
permute norm_qty permt=r(t), strata(group) : ttest norm_qty,
by(group)
This is what I get in return:
Monte Carlo permutation results
Number of strata = 2 Number of obs = 10
command: ttest norm_qty, by(group)
permt: r(t)
permute var: norm_qty
------------------------------------------------------------------------------
T | T(obs) c n p=c/n SE(p) [95% Conf.Interval]
-------------+----------------------------------------------------------------
permt | -4.373186 100 100 1.0000 0.0000 .9637833 1
------------------------------------------------------------------------------
Note: Confidence interval is with respect to p=c/n.
Note: c = #{|T| >= |T(obs)|}
I'm trying to do a comparison of mean values of "norm_qty" between two
groups with a small sample size. Why is it telling me that all my
permutations come out with the same T-statistic as the observed
distribution?
Thank you very much for any help anyone can give me.
Sarah Cabbage
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