[R] Selecting groups with R

jlwoodard john.woodard at wayne.edu
Sat Aug 22 01:03:27 CEST 2009

David Winsemius wrote:
> t.test expects two numeric vectors, not a numeric vector and a  
> grouping indicator.
>  > t.test(dataset[dataset$Color=="RED", "Score"], dataset[dataset 
> $Color=="WHITE", "Score"] )

Thank you again, David!  I also just realized I could have replaced the
comma with a tilde, as in
t.test(Score~Color).  What a difference a character makes!

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