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Suppose that a certain brand of light bulb has a mean life of 450 hours and...

Suppose that a certain brand of light bulb has a mean life of 450 hours and a standard deviation of 73 hours. Assuming the data are bell-shaped: (Show work to get full credit)

a. Would it be unusual for a light bulb to have a life span of 320 hours? 615 hours? Justify each response.

b. According to the Empirical Rule, 99.7% of the light bulbs have a lifetime between what two values?

c. Determine the percentage of light bulbs that will have a life between 304 and 596 hours.

Math   Statistics-And-Probability   
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