Patent US 5,477,334

A method of and apparatus for determining if a given data point having three parameters falls within a population defined by more than four known data points, each data point having the three parameters, the method and apparatus involving determining if the given data point falls within any of a plurality of tetrahedrons, each of the tetrahedrons having four vertices, each of the vertices of each tetrahedron being defined by one of the known data points.