15) When depot service is compared to operator maintenance: A) operator maintenance is slower than depot service. B) competence is higher, but costs may also be higher, with depot service. C) depot service is often the weak link in the chain because of the lack of specific training. D) depot service occurs on-site, while operator maintenance occurs off-site. E) depot service is better for systems connected in parallel, while operator maintenance is preferred for systems connected in series. 16) True or False: TPM (total productive maintenance) is an application of TQM (total quality management) principles to the area of maintenance. 17) True or False: Simulation models and expert systems are useful tools for improving total productive maintenance. 18) A system has three components in series with reliabilities 0.9, 0.7, and 0.8. What is the system reliability? A) 0.315 B) 0.500 C) 0.800 D) 0.504 E) 2.400