In addition to the fine advice you have already received about PROC

NPAR1WAY, let me add some thoughts.

Tests like the Mann-Whitney U do not test the mean. They test the

median. There can be an important difference. Even when the data

are not perfectly normally distributed, the ordinary t-test can have more

power than Mann-Whitney, so think about this. If the data are really far

from normal, then that t-test is not appopriate, but your mean and median

may be so far apart that referring to this as a test of the mean value may

be *massively* misleading.

The other tests that you mention are a lot farther away from a test of the

mean value. K-S and tests like it test whether the entire distribution

of sample A looks like that of sample B. They can have exactly the same

mean and still be vastly different according to their EDFs. Wald-Wolfowitz

doesn't even do that much. It is a test of randomness of sequence based

on runs in the data stream.

Could you explain why you listed these three tests, when at least two

of them are drastically inappropriate for your stated purpose?

HTH,

David

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