title: Confidence intervals for the standardized effect arising in the comparison of two normal populations.
abstract: Confidence intervals for a standardized effect are derived after stabilizing the variance of the Welch t-statistic. Simulation studies demonstrate the viability of the resulting intervals for a wide range of parameter values and sample sizes as small as five. The methodology is extended to the combination of results from several studies, so as to obtain a confidence interval for a representative standardized effect for all the studies. The methods are illustrated on a recent meta-analytic study of systolic blood pressure reduction during a weight reducing regime, as well as the classical Mumford data on psychological intervention and hospital length of stay.
authors.affiliation: Statistical Advisory Service, Imperial College, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Elena
authors.initials: E
authors.lastname: Kulinskaya
authors.forename: Robert G
authors.initials: RG
authors.lastname: Staudte
mesh_terms: D000704:Analysis of Variance; D001794:Blood Pressure; D016001:Confidence Intervals; D006801:Humans; D007902:Length of Stay; D015201:Meta-Analysis as Topic; D015233:Models, Statistical; D011613:Psychotherapy; D015431:Weight Loss