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 ultra batteries and finds that they have a mean lifetime of hours, with a standard deviation of 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. according to chebyshev's theorem, at least 36% of the lifetimes lie between hours according to chebyshev's theorem, at least of the lifetimes lie between 663 hours and 1015 hours. suppose that the distribution is bell-shaped. according to the empirical rule, approximately of the lifetimes lie between 663 hours and 1015 hours. suppose that the distribution is bell-shaped. according to the empirical rule, approximately 99.7% of the lifetimes lie between hours