5. The Russ Trate Traffic Signal Company has decided to install new types of microprocessors in its traffic light assemblies so that these units can more efficiently monitor and control traffic flows. Microprocessors from two suppliers are judged to be suitable for the application. To have more than one source of supply, the Trate Company prefers to buy microprocessors from both suppliers, provided there’s no significant difference in durability. A random sample of 35 computer assemblies of brand A and a sample of 32 computers of brand B are tested. The mean time between failure (MTBF) for the brand A computers is found to be 2,800 hours, and the MTBF for the brand B units is found to be 2,750 hours. Information from industry sources indicates that the population standard deviation is 200 hours for brand A and 180 hours for brand B. At the 0.05 level of significance, is there a difference, is there a difference in durability?