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.

2. People with cholesterol levels between $200$and $240\mathrm{mg}/\mathrm{dl}$are at considerable risk for heart disease. What percent of $14$-year-old boys have blood cholesterol between $200$and $240\mathrm{mg}/\mathrm{dl}$?

Short answer

The percentage of $14$-year-old boys have blood cholesterol between $200$and $240\mathrm{mg}/\mathrm{dl}$is $15\%.$

Step-by-step solution

Given Information 

People with cholesterol levels between $=200and240\mathrm{mg}/\mathrm{dl}$

Age of boys$=14yearold$

Explanation  

People with cholesterol levels between$200and240\mathrm{mg}/\mathrm{dl}$

Find and interpret $P(200\le X\le 240)$

localid="1649921003530" $$\begin{gathered} =normalcdf(lower:200,upper:240,\mu =170,\sigma =30) \\ =0.1488 \end{gathered}$$

There's about a $15\%$chance that a randomly selected $14$-year old boy will have a cholesterol level between $200$and $240\mathrm{mg}/\mathrm{dl}$.