Thanks. I guess what was missing was an indication of how Rcmdr
wanted the data laid out. Mine was in two columns, and R is
perfectly
happy with this if I do "t.test(col1,col2)" so the test is certainly
"applicable to the...data". The catch in Rcmdr is that, because the
menu item is greyed out, you can't get to the dialog box that asks
for
data in the format you mentioned, so you can't tell that Rcmdr is
fussier than R. This should not be a problem as long as I include it
in the documentation for my students.
PS
I share your preference for how the data SHOULD be laid out, but that
was not how the data I had was laid out, and I had no trouble with it
in R and was curious that I could not reproduce my analysis in Rcmdr.
Thanks again for your explanation.
Forwarded message: From: "John Fox" <jfox at mcmaster.ca>
Dear Robert,
The Rcmdr only activates menu items that are applicable to the
data set. In the case of a two-sample t-test, the data set must
at least one two-level factor and one numeric variable. Does that
explain the behaviour you noted?
I hope this helps,
John
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