title: Sample size formula with a continuous outcome for unequal group sizes and unequal variances.
abstract: Guenther derived a simple formula for the accurate computation of equal sample sizes when the two-sample t-test with pooled variance estimate is used. In the present paper, the Guenther formula is generalized to the case of unequal sample sizes. In addition, the case of unequal variances is considered.
authors.affiliation: Department of Methodology and Statistics, Maastricht University, The Netherlands. H.Schouten@Stat.UniMaas.NL
authors.forename: H J
authors.initials: HJ
authors.lastname: Schouten
mesh_terms: D000704:Analysis of Variance; D006801:Humans; D010361:Patients; D018401:Sample Size