Apologies, I made an incorrect statement. The statistics from t-test
with difference variance assumptions are the same if both groups have
the same length. Sorry for troubling everyone again.
On Fri, 2004-10-01 at 13:56, Adaikalavan Ramasamy wrote:
> Peter, thank you! I forgot the to square root
Peter, thank you! I forgot the to square root in calculating sp.
sp <- sqrt( ( (n1-1)*v1 + (n2-1)*v2 )/(n1 + n2 - 2) )
For several simulation runs, the test statistics from both tests are
remarkably similar (difference is less than 10e-16). I naively assumed
that the statistics value should be sl
Adaikalavan Ramasamy <[EMAIL PROTECTED]> writes:
> Could some kindly tell me if I am supposed to be getting the same test
> statistic value with var.equal=TRUE and var.equal=FALSE in t.test ?
>
> set.seed(1066)
> x1 <- rnorm(50)
> x2 <- rnorm(50)
>
> t.test(x1, x2, var.equal=FALSE)$statistic # 0
Could some kindly tell me if I am supposed to be getting the same test
statistic value with var.equal=TRUE and var.equal=FALSE in t.test ?
set.seed(1066)
x1 <- rnorm(50)
x2 <- rnorm(50)
t.test(x1, x2, var.equal=FALSE)$statistic # 0.5989774
t.test(x1, x2, var.equal=TRUE)$statistic # 0.5989774 ???
