Higher order inference for the consensus mean in inter-laboratory studies.
In inter-laboratory studies, a fundamental problem of interest is inference concerning the consensus mean, when the measurements are made by several laboratories which may exhibit different within-laboratory variances, apart from the between laboratory variability. A heteroscedastic one-way random model is very often used to model this scenario. Under such a model, a modified signed log-likelihood ratio procedure is developed for the interval estimation of the common mean. Furthermore, simulation results are presented to show the accuracy of the proposed confidence interval, especially for small samples. The results are illustrated using an example on the determination of selenium in non-fat milk powder by combining the results of four methods. Here, the sample size is small, and the confidence limits for the common mean obtained by different methods produce very different results. The confidence interval based on the modified signed log-likelihood ratio procedure appears to be quite satisfactory.
Department of Mathematics and Statistics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
Gaurav
G
Sharma
Thomas
T
Mathew
D000465:Algorithms; D035843:Biomedical Research / Q000706:statistics & numerical data; D019411:Clinical Laboratory Techniques / Q000592:standards; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D016013:Likelihood Functions; D012044:Regression Analysis; D015203:Reproducibility of Results; D018401:Sample Size; D012643:Selenium / Q000032:analysis
D012643:Selenium