Linked Life Data

7851110

Source:http://linkedlifedata.com/resource/pubmed/id/7851110

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1995-3-15
pubmed:abstractText
We examine the power and sample size requirements for testing an interaction in the situation of a 2 x k factorial design with time to failure as the outcome of interest. Using the distribution of a general test statistic, based on weighted residual sum of squares for testing a general interaction in a 2 x k factorial experiment, we describe the relationship between the power of the test and the size of the sample. In a simulation study, we evaluate the behavior of three commonly used estimators as methods for estimating the parameters of the test statistic. These are the Mantel-Haenszel (MH) method, a method (O/E) based on the ratio of the observed to expected number of events, and the maximum likelihood (MLE) method. We show that in most cases nominal test sizes and appropriate powers are attained using the MLE and MH methods, whereas the O/E method yielded test sizes and powers less than expected. With both large baseline hazard rates and large differences in relative hazard rates, the difference between the simulated and asymptotic powers for all three methods become larger; however, the size of this difference is small and unlikely to seriously affect the use of either the MLE or MH methods. The proposed methods could also be used to calculate the power and sample size for testing a treatment-covariate interaction in a stratified data analysis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0197-2456
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
489-502
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Power considerations for testing an interaction in a 2 x k factorial design with a failure time outcome.
pubmed:affiliation
Department of Preventive Medicine, University of Southern California School of Medicine, Los Angeles 90033.
pubmed:publicationType
Journal Article, Clinical Trial, Comparative Study, Research Support, U.S. Gov't, P.H.S., Randomized Controlled Trial