Statistics

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 selects 1000 Ultra batteries and nds that they have a mean lifetime of 888 hours, with a standard deviation of 99 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 Chebysh-ev's theorem, at least of the lifetimes lie between 690 hours and 1086 hours. (b) According to Chebyshev's theorem, at least 56% of the lifetimes lie between D hours and D hours. (Round your answer to the nearest whole number.)