Question

Follow the method shown in the examples to answer each of the following questions. Use your calculator or the Normal Curve applet to check your answers.

1. Cholesterol levels above $240\mathrm{mg}/\mathrm{dl}$may require medical attention. What percent of $14$-year-old boys have more than $240\mathrm{mg}/\mathrm{dl}$of cholesterol?

Short answer

The percentage of $14$- years old boys have more than $240\mathrm{mg}/\mathrm{dl}$is $1\%$

Step-by-step solution

Given Information 

Cholesterol levels may require medical attention $=240\mathrm{mg}/\mathrm{dl}$above

Age of boys $=14$year old

Explanation 

Cholesterol levels above $240\mathrm{mg}/\mathrm{dl}$may require medical attention.

Find and interpret$P(X>240).$

$$\begin{gathered} P(X>240)=normalcdf(lower:240,upper:9999,\mu =170,\sigma =30) \\ P(X>240)=0.0098 \end{gathered}$$

Final Answer

There's about a $1\%$chance that a randomly selected $14$-year old boy will have a cholesterol level above $240\mathrm{mg}/\mathrm{dl}.$