1. Find the median, the quartiles, and the extremes.
EXAMPLE 1
Making a Box-and-Whisker Plot
Roller Coasters
The heights, in feet, of 10 suspended roller coasters in the United States are 35, 42, 42.5, 60, 60, 70, 76, 78, 81, and 100. Make a box-and-whisker plot of the data.
SOLUTION
STEP 1
Find the median, the quartiles, and the extremes.

2. Plot the five values below a number line.
EXAMPLE 1
Making a Box-and-Whisker Plot
STEP 2
Plot the five values below a number line.
STEP 3
Draw a box connecting the quartiles.
STEP 4
Draw a vertical line through the median.
STEP 5
Draw “whiskers” from the box to both extremes

3. EXAMPLE 2
Interpreting a Box-and-Whisker Plot
Watches
The prices of the watches at a store are summarized in the box-and-whisker plot below. a.
Suppose all of the watches under $31 are on clearance.About what fraction of the watches are on clearance? b.
Suppose all of the watches from $31 to $71 are on sale. About what fraction of the watches are on sale?

4. EXAMPLE 2
Interpreting a Box-and-Whisker Plot
SOLUTION a.
The watches less than $31 are about the same as the number in one of the whiskers, which represents about one quarter of the watches. b.
The watches between $31 and $71 are about the same as the number in the large box of the plot, which represents about half of the watches.

5. GUIDED PRACTICE
for Examples 1 and 2 1.
One weekend, a theater sold the following numbers of tickets to each screening of a new movie. Make a box-and-whisker plot of the data.
497, 429, 746, 469, 504, 464, 326, 302, 509, 467, 401, 499
302
415
501.5
746
468

6. GUIDED PRACTICE 2. What If?
for Examples 1 and 2 2.
What If?
In Example 2, suppose all of the watches under $45 were on clearance. About what fraction of the watches are on clearance?
ANSWER
50%

7. GUIDED PRACTICE
for Examples 1 and 2 3.
In Example 2, is the number of watches between $71 and $120 greater than the number of watches between $16 and $31? Explain.
ANSWER
No , it should be the same because the watches between $71 and $120 represent about 25% of the watches and the watches between $16 and $31 also represent about 25% of the watches.