The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 256.9 and a standard deviation of 64.3. (all units are 1000 cells/mul.) using the empirical rule, find each approximate percentage below.
a. what is the approximate percentage of women with platelet counts within 3 standard deviations of the mean, or between 64.0 and 449.8
b. what is the approximate percentage of women with platelet counts between 128.3 and 385.5
