Question #8 / 20

BIG Corporation produces just about everything bu 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 finds that they have a mean lifetime of 811 hours, with a standard deviation of 98 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______ of the lifetimes lie between 615 hours and 1007 .

(b) According to Chebyshev's theorem, at least 36% of the lifetimes lie between______   and________   .  (Round your answer to the nearest integer.)

(c)  Suppose that the distribution is bell-shaped.  According to the  empirical rule, approximately 68% of the lifetimes lie between_______   and________   .

(d) Suppose that the distribution is bell-shaped.  According to the empirical rule, approximately____________ of the lifetimes lie between 615 hours and 1007 .