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/μL.)

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?

Researchers measured the data speeds for a particular smartphone carrier at 50 airports. The highest speed measured was 72.7

Mbps. The complete list of 50 data speeds has a mean of x=16.65

Mbps and a standard deviation of s=34.84

Mbps.

a. What is the difference between carrier’s highest data speed and the mean of all 50 data speeds?

b. How many standard deviations is that [the difference found in part (a)]?

c. Convert the carrier’s highest data speed to a z score.

d. If we consider data speeds that convert to z scores between −2

and 2 to be neither significantly low nor significantly high, is the carrier’s highest data speed significant?

Use z scores to compare the given values.

Based on sample data, newborn males have weights with a mean of 3227.7g and a standard deviation of 581.8 g. Newborn females have weights with a mean of 3007.4 g and a standard deviation of 578.4 g. Who has the weight that is more extreme relative to the group from which they came: a male who weighs 1700 g or a female who weighs 1700 g?

Since the z score for the male is z=

and the z score for the female is z=,

Use the following cell phone airport data speeds (Mbps) from a particular network. Find the percentile corresponding to the data speed 11.1

Mbps.