A manufacturer of disk drives for notebook computers wants a MTBF of at least 50,000 hours. Recent test results for 15 units were one failure at 10,000 hours, one at 24,000 hours, and two more at 45,000 hours. The remaining units were still running at 60,000 hours.
A) Number of failures per unit-hour =_____failures per hour (round your response to eight decimal places)
B) The mean time between failures (MTBF) is the expected time between a repair and the next failure of a component. MTBF at this time in testing =_______hours