title: An empirical assessment of saddlepoint approximations for testing a logistic regression parameter.
abstract: Saddlepoint methods provide quick and easy approximations to significance levels for conditional tests of logistic regression parameters. We evaluate the accuracies of saddlepoint approximations for three well-known conditional tests: Bartlett's test for no three-factor interaction in a 2 x 2 x 2 table, the test for trend in a series of probabilities, and the exact test of no association in stratified 2 x 2 tables with a common odds ratio. General recommendations are suggested regarding the use of saddlepoint approximations for exact conditional significance levels.
authors.affiliation: Department of Mathematics and Statistics, University of New Mexico, Albuquerque 87131.
authors.forename: E J
authors.initials: EJ
authors.lastname: Bedrick
authors.forename: J R
authors.initials: JR
authors.lastname: Hill
mesh_terms: D008433:Mathematics; D015233:Models, Statistical; D016017:Odds Ratio; D011336:Probability; D011897:Random Allocation; D012044:Regression Analysis