Around what percentage of adults in the USA have stage 2 high blood pressure? Give your answer rounded to two decimal places.

Question

The systolic blood pressure of adults in the USA is nearly normally distributed with a mean of 120 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.

Answer 1

The Z score for sbp=160 is (160-120)/22=40/22=1.8182 approx.

In the normal distribution table 1.8182 corresponds to 0.9655 approx, or 96.55%. This is the percentage of the population with sbp<160, so 100-96.55=3.45% of the population have stage (or type) 2 diabetes (sbp>160).