Optimal Prediction and Tolerance Intervals for the Ratio of Dependent Normal Random Variables

Authors

  • K Krishnamoorthy Department of Mathematics, University of Louisiana at Lafayette, USA
  • Gboyega Adepoju Department of Mathematics, University of Louisiana at Lafayette, USA

DOI:

https://doi.org/10.3329/ijss.v25i1.81041

Keywords:

Equal-tailed tolerance interval; Non-central t; Prediction factor; Tolerance factor

Abstract

A simple exact method is proposed for computing prediction intervals and tolerance intervals for the distribution of the ratio X1/X2 when (X1,X2) follows a bivariate normal distribution. The methodology uses the factors available for computing one-sample prediction intervals and tolerance intervals for a univariate normal distribution. Both one-sided and two-sided intervals are constructed, and the two-sided tolerance intervals are obtained with and without imposing the equal-tail requirement. The results are illustrated using two practical applications that call for the computation of prediction intervals and tolerance intervals for the distribution of the ratio X1/X2. The
first application is an investigation of retroviral contamination in the raw materials used for the manufacture of the influenza vaccine FluMist. The second application is on the cost-effectiveness of a new drug compared to a standard drug.

IJSS, Vol. 25(1), March, 2025, pp 11-22

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Published

2025-04-17

How to Cite

Krishnamoorthy, K., & Adepoju, G. (2025). Optimal Prediction and Tolerance Intervals for the Ratio of Dependent Normal Random Variables. International Journal of Statistical Sciences , 25(1), 11–22. https://doi.org/10.3329/ijss.v25i1.81041

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Section

Original Articles