title: Formulas for combining summary statistics.
abstract: Formulas for computing the combined mean and standard deviation for any number of groups are presented. These formulas produce results that are different from the pooling (averaging) method.
authors.affiliation: Department of Veterans Affairs, VA Long Beach Healthcare System, CA 90822, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Charter
mesh_terms: D006801:Humans; D015233:Models, Statistical