SOLUTION: The lifetime of light bulbs that are advertised to last for 6200 hours are normally distributed with a mean of 6500 hours and a standard deviation of 150 hours. What is the probabi

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Question 810265: The lifetime of light bulbs that are advertised to last for 6200 hours are normally distributed with a mean of 6500 hours and a standard deviation of 150 hours. What is the probability that a bulb lasts longer than the advertised figure?
Found 2 solutions by stanbon, taha:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The lifetime of light bulbs that are advertised to last for 6200 hours are normally distributed with a mean of 6500 hours and a standard deviation of 150 hours. What is the probability that a bulb lasts longer than the advertised figure?
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z(6200) = (6200-6500)/150 = -2
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P(x > 6200) = P(z > -2) = normalcdf(-2,100) = 0.9772
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Cheers,
Stan H.
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Answer by taha(2) About Me  (Show Source):
You can put this solution on YOUR website!
p(x>6200)=
p(z>(5200-6500)/150)=
-300/150=-2
p(z>-2)=
0.0.97