The blood platelets

The blood platelet counts of a group of women have a​ bell-shaped distribution with a mean of 250.8
and a standard deviation of 65.5.
​(All units are 1000 ​cells/μ​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 185.3
and 316.3​?

b.What is the approximate percentage of women with platelet counts between 54.3
and 447.3​?