Exact t-test for 2 independent samples {Rfast}

Exact t-test for 2 independent samples

Description

Exact t-test for 2 independent samples.

Usage

exact.ttest2(x, y)

Arguments

x

A numerical vector with the data.

y

A numerical vector with the data.

Details

This function performs an exact t-test. With few observations, permutation or bootstrap calculation of the p-value is advisable. However, with even fewer observations, one can perform all possible permutations and calculate the exact p-value. This is what this function does. BUT, pay attention, as this works with few samples. If for example each sample contains 15 numbers, you will need a lot of memory (more than 17 GB) for this function to work. the reason is that we create the matrix with all possible permutations first and then perform the two-sample t-test.

Value

A vector with the number of permutations, test statistic and the permutation based p-value.

Author(s)

Michail Tsagris and Manos Papadakis

R implementation and documentation: Michail Tsagris <[e-mail]> and Manos Papadakis <[e-mail]>

References

B.L. Welch (1951). On the comparison of several mean values: an alternative approach. Biometrika, 38(3/4), 330-336.

See Also

boot.ttest2, ttest2, ftest

Examples

x <- rnorm(7)
y <- rnorm(7)
res<-exact.ttest2(x, y)