| Article ID: | iaor19921980 |
| Country: | United States |
| Volume: | 39 |
| Issue: | 3 |
| Start Page Number: | 359 |
| End Page Number: | 368 |
| Publication Date: | Apr 1992 |
| Journal: | Naval Research Logistics |
| Authors: | Chan Wai, Rueda Norma |
With incomplete data the maximum likelihood estimates of the parameters of the Weibull process can only be obtained by solving the likelihood equations iteratively. In this article the authors show that the solution of the likelihood equations may lie outside of the parameter space if none of the processes can be observed from time zero.