Confidence intervals for two-dimensional data with circular tolerances in a gauge R&R study

In this paper, we discuss our application of the Bootstrap method to construct the confidence interval of the diameter for two-dimensional data with circular tolerances in a gauge repeatability and reproducibility study. Factors simulated to validate performance include: the variance component, and sample size. The simulation results show that the Bootstrap method can cover the stated nominal coefficient in most scenarios. There exists a positive correlation between width of confidence intervals and variance components; the width of confidence intervals for diameters is increased when the variance components (σ̂²_x, σ̂²_y or σ̂²_xy) are increased. The coverage proportion is not significantly affected by variance-components. Also, the width of confidence interval for the diameter and coverage proportion is not significantly affected by sample size. One real example based on a nested design is used to demonstrate the application of the proposed method.