mdd.t.test {MDD}R Documentation

MDD for Student's t-Test (Equal Variances)

Description

Calculates minimum detectable difference for a two-sample t-test with equal variances.

Usage

mdd.t.test(n1, n2, mu1, sigma, alpha = 0.05, alternative = "two.sided", 
           return.cis = FALSE)

Arguments

n1,n2 number of subjects in each sample.
mu1 anticipated mean in sample 1 (control).
sigma assumed common standard deviation.
alpha significance level.
alternative indicates the alternative hypothesis and must be one of "two.sided", "greater" or "less". You can specify just the initial letter.
return.cis a logical which indicates whether to return endpoints of confidence intervals or just the MDD.

Details

alternative = "less" is the alternative that has the treatment group mean less than the control group mean.

Value

If return.cis = FALSE, the returned value is the MDD.
If return.cis = TRUE, the returned value is a numeric vector of length two giving the closest values to mu1 that would be significant given the remaining parameters.

Note

For unequal variances, use mdd.satterthwaite

Author(s)

Don Barkauskas (barkda@wald.ucdavis.edu)

See Also

gui.mdd for a GUI version

Examples

mdd.t.test(20, 15, 3.1, .5)
mdd.t.test(20, 15, 3.1, .5, return.cis=TRUE)

[Package MDD version 0.5 Index]