Question 245679: A company installs 5,000 light bulbs, each with an average life of 500 hours, standard deviation of 100 hours, and distribution approximated by a normal curve. How would I Find the approximate number of bulbs that can be expected to last the period of time.Between 500 hours and 675 hours.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! A company installs 5,000 light bulbs, each with an average life of 500 hours, standard deviation of 100 hours, and distribution approximated by a normal curve. How would I Find the approximate number of bulbs that can be expected to last the period of time.Between 500 hours and 675 hours.
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Find the z-value for 500 and for 675.
z(500) = (500-500)/100 = 0
z(675) = (675-500)/100 = 1.75
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P(500 < x < 675) = P(0 < z < 1.75) = 0.46
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The approx. number of bulbs expected to last = 0.46*5000 = 2300
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Cheers,
Stan H.
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