|
Activity Number:
|
335
|
|
Type:
|
Contributed
|
|
Date/Time:
|
Tuesday, July 31, 2007 : 2:00 PM to 3:50 PM
|
|
Sponsor:
|
ENAR
|
| Abstract - #310097 |
|
Title:
|
An Internal Pilot Study with Interim Analysis for Gaussian Linear Models
|
|
Author(s):
|
John Kairalla*+ and Keith E. Muller and Christopher S. Coffey
|
|
Companies:
|
The University of North Carolina at Chapel Hill and University of Florida and The University of Alabama at Birmingham
|
|
Address:
|
Dept. of Biostatistics, 123 Chaucer Court, Carrboro, NC, 27510,
|
|
Keywords:
|
internal ; pilot ; adaptive ; analysis ; power ; design
|
|
Abstract:
|
Combining early stopping rules with internal pilot methods would increase study flexibility, scope, and efficiency for general linear models. I first introduce the model and describe the procedure for a two-stage study design for Gaussian linear models with sample size recalculation based on an updated error variance estimate. Importantly, the design incorporates possible stopping for futility and efficacy at the first stage. Derivations of exact distributions in computable forms allow accurate calculations of power, type I error rate, and expected sample size. The theoretical results jointly cover first and second stage test statistics for both single d.f. hypotheses such as t-tests and more complex hypotheses including multiple group comparisons. The results can be used during planning to create an efficient study with early stopping rules and predictable power properties.
|
- The address information is for the authors that have a + after their name.
- Authors who are presenting talks have a * after their name.
Back to the full JSM 2007 program |
