Comparisons of Approximations to the Percentage Points of the Sample Coeffcient of Variation

It may be of some interest in certain statistical problems to have available percentage points of the sample coefficient of variation (S.C.V.). If the parent population is assumed to be normal, the obtaining of such percentage points from tables of the non-central t distribution might be thought to be simple. However, one does encounter difficulty in using these tables to calculate the percentage points of the S.C.V. One can, as an alternative, use the exact table of Iglewicz (1967). A number of approximations for the percentage points of the S.C.V. exists in the literature. These approximations may be useful as alternatives to either of the tables mentioned above. The applicability of several of these approximations is further enhanced by their simplicity. In this paper we compare these approximate results with the exact ones in order to determine the quality of the approximations.