Quality-adjusted lifetime (QAL) has been playing an important role in clinical trials to evaluate treatments for chronic diseases. Much research has been focused on estimating the mean QAL when the data are subject to right censoring. The estimated mean QAL is often presented with a confidence...

A common problem with laboratory assays is that a measurement of a substance in a test sample becomes relatively imprecise as the concentration decreases. A standard solution is to establish lower limits for reliable measurement. A quantitation limit is a level above which a measurement has...