Assume that the time it takes for bacterial growth on a dairy product after it is taken out of fridge follows an Exponential distribution with a mean of 10 minutes. What is the probability that bacterial growth will not happen in 15 minutes if the dairy product has already been out of the fridge for 10 minutes? A. 0.393 B. 0,777 O C. 0.607 O D. 0.223 Reset Selection

Calculate the relative frequency P(E). You have read 150 of the 500 novels in your home, but your sister Roslyn has read 200, of which only 50 are novels you have read as well. E is the event that a novel has been read by neither you nor your sister. P(E) =

the redundancy? What is the MTTF? What is the reliability over 100 A parking lot has 10 floodlights consisting of 100-watt metal halide bulbs sitting atop 20-foot poles. The failure distribution of the bulbs is best modeled with the two-parameter exponential distribution having a guaranteed lifetime of 1000 hours and a failure rate of .002 failures per day. The floodlights operate for 10 hours per day. Because of the cost to send a crew to replace bulbs, a scheduled replacement interval must be established. (a) Determine a replacement interval in days so that the average number of failed bulbs equals 2 (20 percent). (b) The parking lot is considered unsafe if half or more of the floodlights are inoper- able. Given the replacement interval in (a), what is the probability of more than 4 bulbs having failed before replacement? 3.28 A mean of 0.074 demands per day is observed for components that can be repaired. Repair takes 30 days. How many spare components are needed to meet demands…

Calls arrive at a switchboard a mean of one every 31 seconds. What is the exponential probability that it will take more than 21 seconds but less than 26 seconds for the next call to arrive?