# The blood platelet counts of a group of women have a​ bell-shaped distribution with a mean of 250.8

## The blood platelet counts of a group of women have a​ bell-shaped distribution with a mean of 250.8

The blood platelet counts of a group of women have a​ bell-shaped distribution with a mean of 250.8 150 150 Peter

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​?

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. 