Testing guaranteed exponentiality

Among distributions that are used in survival analysis, the guaranteed exponential is of interest here (for details about the distribution, see Gross and Clark.) In this article, a new approach to testing guaranteed exponentiality is presented. Using engineering data on the number of load cycles until a crack appears in the titanium and steel sheet in aircraft, medical data on the number of weeks tumor patients survived, data on modulus of rupture, a measurement on the breaking strength of lumber, and original I.Q. data on 112 children attending kindergarten classes in San Jose and San Mateo Counties, CA, the present method is illustrated. The first two data sets are known to follow exponential distribution, while the last data set is known to follow normal distribution. The present method confirms these and nonexponentiality for the third data set. A discussion on the merits and disadvantages of the approach is included. Based on simulation, a comparison is made between the power of the present test and EDF test statistic A². The test has excellent power for many nonexponential alternatives.