Chapter 13.1, Problem 20E

To determine

The highest and lowest score on the test.

Answer to Problem 20E

Scores in Exam $\#1$ are higher.

Explanation of Solution

Given information:

Construct a stem-and-leaf plot for Exam $\#1$ . Use the plot to identify the highest and lowest scores on the test.

For Exam $1$ :

  $\begin{array}{l}77,100,77,70,83,89,87,85,81,84,81,78,89,78,88,85,90,92,75,81\\ 85,90,92,75,81,85,100,98,81,78,75,85,89,82,75\end{array}$ .

For Exam $2:$

  $\begin{array}{l}76,78,73,59,70,81,71,66,66,73,68,67,63,67,77,84,87,71,78,78,90\\ 80,77,70,80,64,74,68,68,68\end{array}$

Construct a double stem-and-leaf plot to compare the scores for Exam # $1$ and Exam # $2$ . Which set of scores is higher as a group?

Calculation:

There will be one column of stems, with the leaves representing the unit digits for Exam # $1$ at the right of stems and the leaves representing the units digits for Exam $\#2$ at the left of the stems:

  

Key: $0\left|8\right|1=81$ for Exam $\#1$ and $80$ for Exam $\#2$ .

The double stem-and-leaf plot shows that as a group, the scores in Exam $\#1$ are higher than the scores in Exam $\#2$ .