Choosing the sample size for a trial Let θ denote the effect size of a new treatment, i.e., the difference in mean response between the new treatment and the control. Sample size is determined by: Type I error rate α, and Treatment effect size θ = ∆ at which power 1 − β is to be achieved. Dispute may arise over the choice of ∆. Should investigators use: The minimum effect of interest ∆1, or The anticipated effect size ∆2? 2 Choosing the sample size for a trial Power curves for designs with sample sizes of 500 and 1000
To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.