ABSTRACT
The purpose of this paper is to compare four methods for constructing approximate confidence intervals on the among-group variance component for the unbalanced random one-way model. Monte-Carlo simulation is used to compare the estimated coverage probabilities of these intervals. The comparison is based on a method for generating designs having specified degrees of imbalance. Two of these methods, namely, the one by Thomas and Hultquist Citation[5] and the modified harmonic mean method, appear to be the best in most cases considered.