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In this paper we study a broad class of nonparametric statistics for comparing two diagnostic markers. One can compare the sensitivities of these diagnostic markers over restricted ranges of specificity by selecting an appropriate statistic from this class. As special cases, one can compare the entire area under the receiver-operator curve (Hanley & McNeil, 1982), or one can compare the sensitivities at a fixed common specificity. Usually we would recommend a comparison…

比较配对或非配对诊断指标的一类非参数统计量AI 解读

In this paper we study a broad class of nonparametric statistics for comparing two diagnostic markers. One can compare the sensitivities of these diagnostic markers over restricted ranges of specificity by selecting an appropriate statistic from this class. As special cases, one can compare the entire area under the receiver-operator curve (Hanley & McNeil, 1982), or one can compare the sensitivities at a fixed common specificity. Usually we would recommend a comparison…

病例队列设计的替代方差与效率计算AI 解读

We define a bootstrap sampling plan for the case-cohort design and present bootstrap variance estimates and confidence intervals for the log relative hazard. The coverages of these confidence intervals are found to be near nominal levels in simulations. A simple null variance calculation, based on a superpopulation model, is shown to provide good estimates of the power and efficiency of the case-cohort design.

匹配病例对照研究与死亡时刻并列生存研究的似然计算AI 解读

A recursion is presented which permits rapid computation of a conditional likelihood function which arises in matched case-control studies and survival studies with tied death times. An example with seven parameters and ten large strata, the largest of which contains 29 cases and 52 controls, illustrates the feasibility of the conditional maximum likelihood solution. These methods may be specialized to permit rapid calculation of the conditional maximum likelihood estimate…

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分层与删失下四种生存曲线相等性检验的比较AI 解读

We conducted Monte Carlo experiments to investigate the small sample behaviour of four tests used to analyse stratified censored survival data. The size of the generalized Gehan and Mantel-Haenszel statistics were near nominal level α = 0⋅05. The observed size of the Cox partial likelihood ratio statistic was typically 0⋅065 for fewer than 32 observations per stratum and fell to near nominal levels for larger sample sizes. The continuity corrected Mantel-Haenszel statistic…

基于洛伦兹曲线的无尺度指数分布拟合优度检验AI 解读

The sample Lorenz curve provides a powerful, easily computed goodness-of-fit test for exponentiality which does not depend on the unknown scale parameter. Exact critical values and asymptotic results are given, which can also be used to test the related hypothesis of randomness on an interval. General limit theorems show that the sample Lorenz curve converges almost surely to the population Lorenz curve and that the standardized Lorenz statistic converges to normality…

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