首页 | 本学科首页   官方微博 | 高级检索  
     检索      


Inverse prediction for heteroscedastic response using mixed models software
Authors:Lynn R LaMotte  Jeffrey D Wells
Institution:1. LSU Health Sciences Center, New Orleans, Louisiana, USA;2. Florida International University, Miami, Florida, USA
Abstract:Distributions of a response y (height, for example) differ with values of a factor t (such as age). Given a response y* for a subject of unknown t*, the objective of inverse prediction is to infer the value of t* and to provide a defensible confidence set for it. Training data provide values of y observed on subjects at known values of t. Models relating the mean and variance of y to t can be formulated as mixed (fixed and random) models in terms of sets of functions of t, such as polynomial spline functions. A confidence set on t* can then be had as those hypothetical values of t for which y* is not detected as an outlier when compared to the model fit to the training data. With nonconstant variance, the p-values for these tests are approximate. This article describes how versatile models for this problem can be formulated in such a way that the computations can be accomplished with widely available software for mixed models, such as SAS PROC MIXED. Coverage probabilities of confidence sets on t* are illustrated in an example.
Keywords:Calibration  Outlier detection  Variance components
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号