Asked Dec 8, 2019

The life of light bulbs is distributed normally. The variance of the lifetime is 225and the mean lifetime of a bulb is 530 hours. Find the probability of a bulb lasting for at most 540 hours. Round your answer to four decimal places.


Expert Answer

Step 1

The probability of a bulb lasting for at most 540 hours is calculated below:

Step 2

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540 – 530 P(x<540)= P| 15 : By using Excel fn. = P(Z <0.67) NORM.S.DIST(0.67,TRUE)| = 0.7486


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