### Home > CC2MN > Chapter 9 > Lesson 9.1.5 > Problem9-66

9-66.

Jerome is keeping track of how many books he and his friends have read during the first $100$ days of school. The numbers of books are $12$, $17$, $10$, $24$, $18$, $31$, $17$, $21$, $20$, $14$, $30$, $9$, and $25$. Help Jerome present the data to his teacher.

1. How many pieces of data, or observations, does Jerome have?

Refer to the data.

2. Make a stem-and-leaf plot of the data.

$\begin{array}{l|l} \text{Note: 4} & \ 1 \text{ means }41 \quad \end{array}$

$\begin{array}{r|l} 0 & 9 \\ 1 & 0, 2, 4, 7, 7, 8\\ 2 & 0, 1, 4, 5\\ 3 & 0, 1 \end{array}$

3. Jerome wants to present the data with a plot that makes it possible to calculate the mean and the median. Can he do this with a stem-and-leaf plot? He is not asking you to calculate them, but he wants you to tell him if it is possible and why.

• Does the stem-and-leaf plot show all of the data points?

1. Use the stem-and-leaf plot to describe how the data is spread. That is, is it spread out, or is it concentrated mostly in a narrow range?

Where are most of the values concentrated?

2. Would it be helpful for Jerome to create a dot plot to display and analyze the data from problem 9-66? Why or why not?

Would it be practical to put this information into a dot plot?

No, there are too many data points that do not repeat.

Make a stem-and-leaf plot using the eTool below.
Click the link at right for the full version of the eTool: 9-66 HW eTool (Desmos)