Published online by Cambridge University Press: 14 July 2016
Many random variables arising in problems of geometric probability have intractable densities, and it is very difficult to find probabilities or percentage points based on these densities. A simple approximation, a generalization of the chi-square distribution, is suggested, to approximate such densities; the approximation uses the first three moments. These may be theoretically derived, or may be obtained from Monte Carlo sampling.
The approximation is illustrated on random variables (the area, the perimeter, and the number of sides) associated with random polygons arising from two processes in the plane. Where it can be checked theoretically, the approximation gives good results. It is compared also with Pearson curve fits to the densities.
Research supported by the National Research Council of Canada, by the U.S. Office of Naval Research, Contract No. N00014–76–C–0475, and by the U.S. Army Research Office, Grant DAAG 29–77–G–0031.