SOLUTION: The maintenance department at the main campus of a large state university receives daily requests to replace fluorecent lightbulbs. The distribution of the number of daily requests

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Question 1198774: The maintenance department at the main campus of a large state university receives daily requests to replace fluorecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 42 and a standard deviation of 3. Using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 39 and 42?
Answer by Shin123(626) About Me  (Show Source):
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39 is 1 standard deviation away from the mean. By the 68-95-99.7 rule, approximately 68% of the number of light bulb replacement requests are between 39 and 45. Since the bell-shaped distribution is symmetrical around the mean, 34% of the number of light bulb replacement requests are between 39 and 42.