The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 258.7 and a standard deviation of 63.5. (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 68.2 and 449.2? b. What is the approximate percentage of women with platelet counts between 195.2 and 322.2?

a)

And from the empirical rule we know that this probability is 0.997 or 99.7%

b)

Using the z score we have:

And within one deviation from the mean we have 68% of the values

Step-by-step explanation:

For this case we defien the random variable of interest X as "blood platelet counts" and we know the following parameters:

Part a

We can use the z score formula given by:

And we want this probability:

And from the empirical rule we know that this probability is 0.997 or 99.7%

Part b

For this case we want this probability:

Using the z score we have:

And within one deviation from the mean we have 68% of the values

the answer is a

step-by-step explanation: