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?

   Hint (a):

   Refer to the data.

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

   Answer (b):

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

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

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.

4. 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?

   Hint (d):

   Where are most of the values concentrated?

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

   Hint (e):

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

   Answer (e):

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