# Empirical Rule: The lifetimes of light bulbs of a particular type are normally distributed.

The lifetimes of light bulbs of a particular type are normally distributed with a mean of 370 hours and a standard deviation of 5 hours. What percentage of the bulbs have lifetimes that lie within one standard deviation of the mean on either side? Use the 68-95.99.7 Rule.

Please give a through and simplistic explanation in the answer.

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#### Solution Summary

The solution provides step by step method for the calculation of probability using the Z score. Formula for the calculation and Interpretations of the results are also included.

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