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作者:DINSE, GE; LARSON, MG
作者单位:Harvard University; Harvard T.H. Chan School of Public Health
摘要:A recharacterization of the semi-Markov model described by Lagakos, Sommer and Zelen (1978) permits the nonparametric maximum likelihood estimators to be expressed in terms of familiar and easily computable quantities, such as event-specific hazard estimators and Kaplan and Meier (1958) survival estimators. In addition to simplifying the calculation and clarifying the interpretation of the previously derived estimators, this reformulation also facilitates the estimation of covariance terms and...
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作者:TSAI, CL
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作者:STEFANSKI, LA; CARROLL, RJ; RUPPERT, D
作者单位:University of North Carolina; University of North Carolina Chapel Hill
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作者:BARDSLEY, WG; MCGINLAY, PB; WRIGHT, AJ
摘要:The performance of the F test in identifying the correct number of components in exponential functions is investigated by mathematical and computational techniques. Uncoupled systems can be most easily identified when the relaxation times are widely separated but the exponential functions encountered in pharmacokinetics and biochemistry are linked in that the amplitudes and eigenvalues are not independent. In such systems correct model discrimination occurs as the relaxation times become close...
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作者:KOUTRAS, M
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作者:MCLEISH, DL; SMALL, CG
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作者:HOUGAARD, P
摘要:A new three-parameter family of distributions on the positive numbers is proposed. It includes the stable distributions on the positive numbers, the gamma, the degenerate and the inverse Gaussian distributions. The family is characterized by the Laplace transform, from which moments, convolutions, infinite divisibility, unimodality and other properties are derived. The density is complicated, but a simple saddlepoint approximation is provided. Weibull and Gompertz distributions are naturally m...
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作者:ANSLEY, CF; KOHN, R
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作者:MARTIN, RJ
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作者:PORTIER, CJ
摘要:In most survival-sacrifice experiments for the detection and quantification of risks from chronic exposure to chemical agents, the onset of the condition of interest is not clinically observable. Cancer is typically such an event. In this paper, an approximate maximum likelihood method is proposed for parametric estimation of the distribution of unobservable tumour onset times in the presence of competing risks, when cause-of-death information is unavailable.