-
作者：HOUGAARD, P
摘要：A class of continuous multivariate lifetime distributions is proposed. The dependence between individuals in a group is modelled by a group specific quantity, which can be interpreted as an unobserved covariate common to the individuals in the group and assumed to follow a positive stable distribution. It is possible to include covariates in the model and discuss whether the dependence is still present after specific covariates are taken into account. If the conditional hazards are proportiona...
-
作者：GASSER, T; SROKA, L; JENNENSTEINMETZ, C
作者单位：Ruprecht Karls University Heidelberg
摘要：A nonparametric estimator of residual variance in nonlinear regression is proposed. It is based on local linear fitting. Asymptotically the estimator has a small bias, but a larger variance compared with the parametric estimator in linear regression. Finite sample properties are investigated in a simulation study, including a comparison with other nonparametric estimators. The method is also useful for spotting heteroscedasticity and outliers in the residual at an early stage of the data analy...
-
作者：COX, DR; SOLOMON, PJ
作者单位：University of Adelaide
摘要：Procedures are discussed for the detailed analysis of distributional form, based on many samples of size r, where especially r = 2, 3, 4. The possibility of discriminating between different kinds of departure from the standard normal assumptions is discussed. Both graphical and more formal procedures are developed and illustrated by some data on pulse rates.
-
作者：LJUNG, GM
-
作者：ALTMAN, DG; ANDERSEN, PK
作者单位：University of Copenhagen
摘要：From a Cox regression model for censored survival data, it is possible to estimate the t-year survival probability for an individual with covariates zO, say. The variance of the estimate, however, depends not only on the value of the estimate but also on the particular covariate pattern zO. The dependence on zO is studied and approximations to the variance are suggested which can be computed much more simply.
-
作者：LEE, CH; MARTIN, RD
-
作者：BAUER, P
摘要：Conservative critical limits for discrete sequential boundaries are derived, when the number of decision times and group sizes are not fixed in advance. The method at any stage of the sequential experiment requires only the joint distribution of the test statistics at the last two inspection times.
-
作者：QUESENBERRY, CP; JEWELL, NP
摘要：Jewell (1985) described an iterative method of estimating parameters in the linear regression model from data collected from stratified samples of the dependent variable with no parametric assumptions on the residual distribution. The present paper considers an alternative iterative technique which is generally superior in terms of efficiency, often by a considerable amount. The method is extended to cover stratified sampling on a design variable which is correlated with the dependent variable...
-
作者：SAXENA, RR; SINGH, P; SRIVASTAVA, AK
作者单位：Indian Council of Agricultural Research (ICAR); ICAR - Indian Agricultural Statistics Research Institute
摘要：A new sampling scheme, with probability of inclusion proportional to size, is proposed for a sample of given size n. It satisfies many requirements of a good sampling scheme under conditions usually met in practice. Empirical exploration of the feasibility of the proposed sampling scheme and of the stability of its variance, shows satisfactory performance.
-
作者：WHITEHEAD, J
摘要：The bias of maximum likelihood estimates calculated at the end of a sequential procedure is investigated. For the two sequential designs considered in detail, the sequential probability ratio test and the triangular test, this bias is appreciable. A method of calculating an adjusted estimate with reduced bias is described, and an approximation to the standard error of the new estimate is provided. Examples of the implementation of the method are given, and it''s advantages and disadvantages re...
