BIG Corporation produces just about everything but is currently interested in the lifetimes of its batteries, hoping to obtain its share of a market boosted by the popularity of portable CD and MP3 players. To investigate its new line of Ultra batteries, BIG randomly selects1000

Ultra batteries and finds that they have a mean lifetime of823 hours, with a standard deviation of92

hours. Suppose that this mean and standard deviation apply to the population of all Ultra batteries. Complete the following statements about the distribution of lifetimes of all Ultra batteries.

(a) According to Chebyshev's theorem, at least? 36%, 56%, 75%, 84%, 89% of the lifetimes lie between639 hours and1007 hours.

(b) According to Chebyshev's theorem, at least8/9 (about89%) of the lifetimes lie between hours and hours. (Round your answer to the nearest whole number.)