[R] Independant-samples t-test

[Mark Myatt]

Dr Stuart Leask <stuart.leask at nottingham.ac.uk> writes:
>I can't find a 'group' option in t.test (library ctest).
>
>(eg. X = normally-distributed rating scale
>Y = sex
>I'd like to compare the means by sex, but can't do t.test(X,group=Y) or
>whatever).

Index the vector by group:


        t.test(x[sex == 1], x[sex == 2])

should do the trick. You could try:

        summary(aov(sex~group))

which is equivalent but assumes equal variances.

Mark


--
Mark Myatt


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