Question

The distribution of cholesterol levels in teenage boys is approximately normal withnbsp mu equals 170 and sigma equals 30 ​(Source: U.S. National Center for Health​ Statistics). Levels above 200 warrant attention. Find the probability that a teenage boy has a cholesterol level greater than 225.

Answer 1

Answer: 0.0336

Step-by-step explanation:

Given : The distribution of cholesterol levels in teenage boys is approximately normal with mean :$\mu= 170$

Standard deviation : $\sigma= 30$

The formula for z-score is given by :-

$z=\dfrac{x-\mu}{\sigma}$

For x=225

$z=\dfrac{225-170}{30}=1.83$

The p-value =$P(z>1.83)=1-P(z$

$=1-0.966375=0.033625\approx0.0336$

The probability that a teenage boy has a cholesterol level greater than 225 =0.0336