Question

The systolic blood pressure of adults in the USA is nearly normally distributed with a mean of 119 and standard deviation of 22 .
Someone qualifies as having Stage 2 high blood pressure if their systolic blood pressure is 160 or higher.
a. Around what percentage of adults in the USA have stage 2 high blood pressure? Give your answer rounded to two decimal places.
%
b. If you sampled 2000 people, how many would you expect to have BP> 160? Give your answer to the nearest person. Note: I had a bit of an issue encoding rounded answers, so try rounding both up and down if there's an issue!
people
c. Stage 1 high BP is specified as systolic BP between 140 and 160. What percentage of adults in the US qualify for stage 1?
%
d. Your doctor tells you you are in the 30th percentile for blood pressure among US adults. What is your systolic BP? Round to 2 decimal places.
lbs

Answer 1

Define the standard random variable Z as Where X denotest the blood pressure

a) Using the normal table we get

So the percetnage is 3.14%

b) Expected number of people with BP>160 is

that is around 63 people are expected to have BP>160.

c) Using normal table

Hence the percentage is 13.96%

d) From normal table we get

So 107.47 is the 30th percentile of the BP