Apply the 68-95-99.7 rule to answer the question.
-The lifetimes of light bulbs of a particular type are normally distributed with a mean of 310 hours and a standard deviation of 9 hours. What percentage of the bulbs have lifetimes that lie within 2 standard deviations to either side of the mean?

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Quizplus · Accepted Answer

The 68-95-99.7 rule, also known as the empirical rule, states that for a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, 95% falls within two standard deviations, and 99.7% falls within three standard deviations. Therefore, the percentage of bulbs with lifetimes within 2 standard deviations of the mean is 95%.

Apply the 68-95-99.7 Rule to Answer the Question