Annals of Occupational Hygiene Advance Access originally published online on December 3, 2008
Annals of Occupational Hygiene 2009 53(2):167-171; doi:10.1093/annhyg/men076
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Inference on the Symmetric-Range Accuracy
1 Department of Mathematics, University of Louisiana at Lafayette, Lafayette, LA 70508, USA
2 Department of Mathematics and Statistics, University of Maryland, Baltimore, MD 21259, USA
* Author to whom correspondence should be addressed. Tel: +337 482 5283; fax: +337 482 5346; e-mail: krishna{at}louisiana.edu
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 normal distribution. We propose confidence limits for A based on the concept of a ‘generalized confidence interval’. A convenient approximation is also provided for computing the confidence limit. Monte Carlo evaluation indicates that the proposed approaches are very satisfactory even for small samples. The statistical procedures are illustrated using an example involving carbon monoxide monitoring.
Keywords: bias • coverage probability • non-central chi-square distribution • normal approximation • tolerance intervals
Received September 21, 2008; in final form October 28, 2008