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

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=(x-\mu)/(\sigma)`

For x=225

`z=(225-170)/(30)=1.83`

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

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

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