The symmetric-range accuracy under a one-way random model with balanced or unbalanced data.
Krishnamoorthy K; Mathew T
Ann Occup Hyg 2013 Aug; 57(7):953-961
The symmetric-range accuracy A of a sampler is defined as the fractional range, symmetric about the true concentration, that includes a specified proportion of sampler measurements. In this article, we give an explicit expression for A assuming that the sampler measurements follow a one-way random model so as to capture different components of variability, for example, variabilities among and within different laboratories or variabilities among and within exposed workers. We derive an upper confidence limit for A based on the concept of a 'generalized confidence interval'. A convenient approximation is also provided for computing the upper confidence limit. Both balanced and unbalanced data situations are investigated. Monte Carlo evaluation indicates that the proposed upper confidence limit is satisfactory even for small samples. The statistical procedures are illustrated using an example.
Models; Samplers; Measurement-equipment; Laboratories; Workers; Exposure-levels;
Author Keywords: coverage probability; generalized confidence interval; generalized pivotal quantity; non-central chi-square distribution; upper confidence limit
Kalimuthu Krishnamoorthy, Department of Mathematics, University of Louisiana, Lafayette, LA 70508
Annals of Occupational Hygiene
University of Maryland, Baltimore