Analyzing Graphs

So far, you’ve learned how to display data graphically.   Now, we will use the graphs to analyze the data and find measures of center and variability.     Graphical displays of data can also be helpful when comparing two or more sets of data.

Example:

The table shows the number of wins of two middle school basketball teams for the past ten years.

Lakeview MS 24 26 24 10 8 11 8 13 16 10
Mountainside MS 14 11 11 16 14 9 18 11 16 15
  1. Which team had a greater range of wins?
  2. What is the mean number of wins for each team?

To be able to compare the data easily, let’s arrange the data above into a back-to-back stem-and-leaf plot.

Lakeview MS Stem Mountainside MS
8 8

0 0 1 3 6

4 4 6

Key: 4|2 = 24 games

0

1

2

9

1 1 1 4 4 5 6 6 8

 

Key: 1|1 = 11 games

3. Which middle school has a more consistent number of wins?

4. Find the median number of wins for each team.

You can watch a video of these solutions if you had trouble getting the correct answer.

 

(source)