Answer
81.5% of the bulbs will have a mean lifetime between 547 and 706 hours.
Work Step by Step
Using the Empirical rule, we have:
x̅ - 1s = 600 - 53 = 547
x̅ + 3s = 600 + 3(53) = 706
68/2 = 34% and 95/2 = 47.5%
34 + 47.5 = 81.5%
Hence, 81.5% of the bulbs will have a mean lifetime between 547 and 706 hours.
