| Abstract: | The within‐device precision for quantitative assays is the square root of the total variance, which is defined as the sum of the between‐day, between‐run, and within‐run variances under a two‐stage nested random‐effects model. Currently, methods for point and interval estimations have been proposed. However, the literature on sample size determination for within‐device precision is scarce. We propose an approach for the determination of sample size for within‐device precision. Our approach is based on the probability for which the 100(1 ? α)% upper confidence bound for the within‐device precision smaller than the pre‐specified claim is greater than 1 ? β. We derive the asymptotic distribution of the confidence upper bound based on the modified large‐sample method for sample size determination and allocation. Our study reveals that the dominant term for sample size determination is the between‐day variance. Results of simulation studies are reported. An example with real data is used to illustrate the proposed method. Copyright © 2014 John Wiley & Sons, Ltd. |
