A company produces light bulbs whose life follows a normal distribution, with mean (1355) hours and standard deviation (105) hours. If we choose a light bulb randomly a. What is the probability that its lifetime will be between 1280 and 1740 hours? b. What is the lifetime in hours that 55 % of the bulbs exceed?

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A: The mean is 120 minutes and standard deviation is 30 minutes.

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Q: A normal population had a mean of 70 and a standard deviation of 12. You select a random sample of…

A: μ = 70σ = 12n = 9P(x¯>73) = ?

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A: Given that, Mean = 130 Standard deviation = 35 Sample size = 25

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