Study Guide and Intervention (continued) - MathnMind

13-5
Parallel Box-and-Whisker Plots Two sets of data can be compared by drawing
parallel box-and-whisker plots along the same number line.
Example
The number of games won by the six
Central Division baseball teams of the National League
during the 2000 and the 1998 baseball seasons are shown
in the table at the right. Draw a parallel box-and-whisker
plot for the data and compare the data.
Step 1 With the data ordered from least to greatest, determine
the quartiles for each year.
For 2000, the median is 72.5 games won. The lower
Houston
Pittsburgh
72
69
102
69
quartile, Q1 , is 69. The upper quartile, Q3 , is 85.
The interquartile range is 85 69 16.
Check for outliers: 69 1.5(16) 45 and 85 1.5(16) 109.
There are no numbers less than 45 or greater than 109.
Therefore, there are no outliers.
Chicago 65 90
For 1998, the median is 80 games won. The lower quartile, Q1 , is 74. The upper
quartile, Q3 , is 90. The interquartile range is 16.
Check for outliers: 74 1.5(16) 50 and 90 1.5(16) 114.
There are no numbers less than 50 or greater than 114.
Therefore, there are no outliers.
Step 2 Draw the box-and-whisker plots along the same number line.
65 70 75 80 85 90 95 100 105
Step 3 Use the box-and-whisker plots to compare the data.
The range of games won is about the same for each year, but in general, the
number of games won was higher in 1998. The median was also higher for 1998.
Exercises
NAME ______________________________________________ DATE ____________ PERIOD _____
Study Guide and Intervention (continued)
Box-and-Whisker Plots
Draw a parallel box-and-whisker plot for each pair of data. Compare the data.
1. A: 18, 41, 72, 45, 68, 75, 89, 34 2. A: 18, 34, 45, 34, 23, 32, 43, 14, 15
B: 38, 39, 74, 56, 78, 68, 49, 78 B: 19, 20, 40, 78, 56, 45, 35, 45, 91
10 20 30 40 50 60 70 80 90
B
2000
A
1998
10 20 30 40 50 60 70 80 90
© Glencoe/McGraw-Hill 806 Glencoe Algebra 1
A
Team 2000 1998
St. Louis 95 83
Cincinnati 85 77
Milwaukee 73 74
B