Systems testing and statistical test data coverage

Coverage is often used to determine when unit modules have been sufficiently tested. It is difficult to apply the same approach to whole systems. An additional problem is that coverage has no obvious reliability interpretation. A form of coverage called statistical coverage is described that solves some of the problems of systems level coverage and which also has a reliability interpretation. Statistical coverage is based on ideas from statistical testing. Statistical testing is reviewed and new results are introduced that are needed for statistical coverage, and which can also be applied to statistical testing.