Robert W. Hayden
hayden at mv.mv.com
Sat Feb 10 02:49:49 CET 2007
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.
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 current
> data set. In the case of a two-sample t-test, the data set must include
> at least one two-level factor and one numeric variable. Does that
> explain the behaviour you noted?
> I hope this helps,
| ^ |
| / Robert W. Hayden
| | in the old library
| | 212 Main Street
| / P. O. Box 450
| | ^ North Troy, VT 05859
L__L (802) 988-2587
Map of VT bob at statland.org
Communications sent to Plymouth State will not reach me.
More information about the R-sig-teaching