n.welch.test {samplesize} | R Documentation |
Function computes sample size for Student's t-test with Welch approximation for unequal variances
n.welch.test(power = 0.8, alpha = 0.95, mean.diff = 2, sd.est1 = 1, sd.est2 = 2.65)
power |
required power 1-beta |
alpha |
required Level I-error 1-alpha |
mean.diff |
required minimum difference between group means |
sd.est1 |
standard deviation in group 1 |
sd.est2 |
standard deviation in group 2 |
sample size |
Total sample size N |
sample size n1 |
sample size in group 1 |
sample size n2 |
sample size in group 2 |
Ralph Scherer
Bock J., Bestimmung des Stichprobenumfangs fuer biologische Experimente und kontrollierte klinische Studien. Oldenbourg 1998
n.indep.t.test.neq(), n.paired.t.test(), n.indep.t.test.eq()
n.welch.test(power = 0.8, alpha = 0.95, mean.diff = 2, sd.est1 = 1, sd.est2 = 2.65)