Sorry, a Google search shows that your description is apparently specific in
the psychology literature to what the statistics literature would call
Tukey's HSD multiple comparison procedure.

The calculations are straightforward
http://davidmlane.com/hyperstat/B95118.html
http://web.umr.edu/~psyworld/tukeyssteps.htm
except for determining p-values or critical values. For that, you could
translate
http://lib.stat.cmu.edu/apstat/190
from Fortran into VBA if you do not care to use a table.

Jerry

"Ross" wrote:

excel does not have such a built-in function so i tried analyse-it and
INERST13.XLS from web. both don't have any clear instructions how the
dataset should be input. is anybody knowing how to best perform such a test
in Excel? thx in advance!!