Please Help Will Fan And Medal
A component in a music system has a life expectancy of 2,400 hours with a standard deviation of 300 hours. If an average person listens to music for 1,000 hours in a year, the probability that the component lasts for more than 3 years is
%.
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Question

Please Help Will Fan And Medal
A component in a music system has a life expectancy of 2,400 hours with a standard deviation of 300 hours. If an average person listens to music for 1,000 hours in a year, the probability that the component lasts for more than 3 years is 
%.
NextReset

jeff666 · Answer

Probability that a standard normal variate will exceed 2 is 0.02275, or about 2.3%.  This is the probability that the component lasts for more than 3 years.