Confidence intervals for the standardized effect arising in the comparison of two normal populations.
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.
Kulinskaya
Elena
E
Statistical Advisory Service, Imperial College, Sir Alexander Fleming Building, South Kensington Campus, London SW7 2AZ, UK.
Staudte
Robert G
RG
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