Yang S
Department of Mathematics, Texas Tech University, Lubbock 79409, USA.
Biometrics. 1998 Sep;54(3):1040-52.
Some new scale estimators for the censored two-sample accelerated life model are introduced. They are zeros of some integrated weighted difference between the two cumulative hazard estimators. These estimators are asymptotically normal. The weight is chosen to result in estimators whose asymptotic variances do not involve the destiny functions and can be easily estimated. This provides a fast and simple means of statistical inference in the censored two-sample accelerated life model. Through investigating the asymptotic relative efficiency at some important censoring submodels and the finite example behaviors in various numerical studies, we obtain some estimators with very competitive performance. From the new class of scale estimators, some lack-of-fit tests for the accelerated life model are also derived. These tests are related to Gill-Schumacher type tests and require little extra computing time once the estimator is obtained. The estimators and tests are illustrated in two applications. For a vaginal cancer data set for rats, the effect of pretreatment regime was found to be well described by the two-sample accelerated life model. For a data set on progression of ovarian cancer, it was found that the effect of grade of disease could not be described either by the two-sample proportional hazards model or the two-sample accelerated life model.
介绍了一些用于删失两样本加速寿命模型的新尺度估计量。它们是两个累积风险估计量之间某种积分加权差的零点。这些估计量渐近正态。权重的选择使得估计量的渐近方差不涉及密度函数且易于估计。这为删失两样本加速寿命模型提供了一种快速且简单的统计推断方法。通过研究在一些重要删失子模型下的渐近相对效率以及各种数值研究中的有限样本行为，我们得到了一些具有非常有竞争力性能的估计量。从新的尺度估计量类别中，还导出了一些加速寿命模型的失拟检验。这些检验与吉尔 - 舒马赫类型检验相关，一旦获得估计量，几乎不需要额外的计算时间。估计量和检验在两个应用中进行了说明。对于大鼠阴道癌数据集，发现两样本加速寿命模型能很好地描述预处理方案的效果。对于卵巢癌进展的数据集，发现疾病分级的效果既不能用两样本比例风险模型也不能用两样本加速寿命模型来描述。
