P.Dalgaard at biostat.ku.dk
Fri Jul 6 11:25:09 CEST 2007
> Hi, how can I solve a problem without the function t.test???
> for example:
Hints: Take out your statistics textbook and look up the formulas for
the two-sample t.
You'll probably (there can be some variation depending on the book) find
that you need to compute
- difference of means
- sd for each group
- pooled sd
- s.e. of differences of means
all of which you can do easily in R, once you have the formulas. Then
calculate the t statistic and the corresponding p value, either using a
table or R's function for the t distibution.
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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