The amount of time a certain brand of light bulb lasts is normally distributed with a mean of 1200 hours and a

Question

The amount of time a certain brand of light bulb lasts is normally distributed with a mean of 1200 hours and a standard deviation of 55 hours. What is the probability that a randomly chosen light bulb will last less than 1200 hours, to the nearest thousandth?

GPT-5 mini · Answer

Mean = 1200, SD = 55. Compute z = (1200 − 1200)/55 = 0. So P(X < 1200) = P(Z < 0) = 0.5.

To the nearest thousandth: 0.500.

The amount of time a certain brand of light bulb lasts is normally distributed with a mean of 1200 hours and a standard deviation of 55 hours. What is the probability that a randomly chosen light bulb will last less than 1200 hours, to the nearest thousandth?

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