Solving maximum likelihood equations for two-parameter software reliability models using grouped data

Existence conditions are given for maximum likelihood parameter estimates for several commonly employed two-parameter software reliability models. For these models, the maximum likelihood equations can be expressed in terms of a single equation in one unknown. Bounds are given on solutions to these single equations problems to serve as initial intervals for search algorithms like bisection. Uniqueness of the solutions is established in some cases. Results are given for the case of grouped failure data