I have two pairs of related vectors
x1,y1
and
x2,y2
I wish to do a test for differences in means of x1 and y1, ditto x2 and y2.
I am getting odd results. I am not sure I am using 'pt' properly...
I have not included the raw vectors as they are long. I am interested if I
am using R properly...
> c(length(x1), length(y1), length(x2), length(y2))
[1] 3436 1619 2677 2378
First where the T-stat and the DF do not give the same result as 't.test'
when passed into 'pt'
> t.1 <- t.test(x1, y1)
> 2 * pt(t.1$statistic, t.1$parameter)
t
1.353946
> t.1$p.value
[1] 0.646054
I would have thought these would have been the same. Like below....
> t.2 <- t.test(x2, y2)
> 2 * pt(t.2$statistic, t.2$parameter)
t
0.8679732
> t.2$p.value
[1] 0.8679732
This is what I expect.
clearly I misunderstand some thing. What is it?
cheers
Worik
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