Chapter 2, Problem 1SE

Pulse Rates The dotplot shown is for resting pulse rates of 125 people (according to NHANES, National Health and Nutrition Examination Survey).

Many sources say the resting pulse should not be more than 100.

a. How many of the 125 people had resting pulse rates of more than 100?

b. What percentage of people had resting pulse rates of more than 100?

To determine

Find the number of people who have resting pulse rate of more than $100$.

Answer to Problem 1SE

The required number is $4$.

Explanation of Solution

The dot plot represents the resting pulse rates of 125 people. Here, the horizontal axis in the provided dot plot represents the resting pulse rate and each resting pulse rate has the dots above it, where each of these dots represents one person having that particular resting pulse rate.

So, the number of dots above particular pulse denotes the frequency of that pulse. By looking at the graph, it is clear that there are total of $4$ dots corresponding to the resting pulse rates of more than $100$.

Hence, there are 4 people who have resting pulse rates of more than 100.

To determine

Find the percentage of people having resting pulse rate of more than $100$.

Answer to Problem 1SE

The required percentage is $3.2\%$.

Explanation of Solution

Calculation:

The number of people who have the resting pulse rates of more than $100$ is calculated to be $4$ and there are total of $125$ people.

The percentage of people having resting pulse rate of more than $100$ can be calculated as shown below:

$\begin{array}{c}\left(\begin{array}{l}\text{Percentage of people}\\ \text{having resting pulse rates}\\ \text{of more than 100}\end{array}\right)\text{ = }\frac{\left(\begin{array}{l}\text{Number of people having resting }\\ \text{pulse rates of more than 100 }\end{array}\right)}{\text{Total number of people}}\times 100\\ =\frac{4}{125}\times 100\\ =0.032\times 100\\ =3.2\%\end{array}$

Hence, $3.2\%$ of people had resting pulse rates of more than 100.