The blood platelet counts of a group of women have a​ bell-shaped distribution with a mean of 257.1 and a standard deviation of 69.6. ​(All units are 1000 ​cells/mu​L.) Using the empirical​ rule, find each approximate percentage below. a. What is the approximate percentage of women with platelet counts within 1 standard deviation of the​ mean, or between 187.5 and 326.7​? b. What is the approximate percentage of women with platelet counts between 48.3 and 465.9​?