title: An age-adjusted trend test for the tumor incidence rate for multiple-sacrifice experiments.
abstract: The nonparametric age-adjusted trend test for the tumor incidence rate proposed by Malani and Lu (1993, Communications in Statistics--Theory and Methods 22, 1557-1584) is modified in two ways to improve the size of the test. First, the tumor incidence rate is constrained to be nonnegative, and second, a conditional variance is used in place of the asymptotic variance based on the delta method. A Monte Carlo simulation study demonstrates the improvement in size of test. The proposed test can be viewed also as a modification of the two-group test of Dewanji and Kalbfleisch (1986, Biometrics 42, 325-341), although their maximum likelihood routine is based on a different formulation of the problem.
authors.affiliation: Division of Biometry and Risk Assessment, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
authors.forename: R L
authors.initials: RL
authors.lastname: Kodell
authors.forename: H
authors.initials: H
authors.lastname: Ahn
mesh_terms: D000367:Age Factors; D016022:Case-Control Studies; D006801:Humans; D015994:Incidence; D016013:Likelihood Functions; D009010:Monte Carlo Method; D009369:Neoplasms / Q000453:epidemiology* / Q000401:mortality; D011336:Probability; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D015996:Survival Rate