A problem in forensic science

SUMMARY The problem of deciding whether two sets of fragments have come from a common source frequently arises in forensic science. This paper provides a solution in the realistic case where the distribution is nonnormal. The normal case is also discussed because it is there easier to understand the nature of the solution and, in particular, its relationship to significance tests. The solution requires the distribution function of the product of standardized normal quantities which is tabulated in the appendix.