Box & Whisker
Plot
Chantal Alano, Trisha
Jiang, Jordan
Armstrong
Period 1
What is a Box & Whisker Plot?


Used when there is a large amount of data
Shows:







Median(Q2)
Minimum
Maximum
Lower Quartile(Q1)
Upper Quartile(Q3)
Sometimes outliers
Inter Quartile Range (IQR)
What is the Inter Quartile
Range (IQR)?
Q3-Q1=IQR
Example
 7,
7, 9, 9, 10, 10, 11, 11, 12, 13
 Used to find number of sled dogs left
competing in race
Data Necessary
 Single
Sets
 Multiple Sets
 Numerical
Real Life Data
 Data
was collected from Arcola’s 7th
grade Honors Algebra class
Hours of Electronics Used Per Day
 2.5, 4.5, 4.5, 1, 1.5, 1, 3, 2, 1, 6, 3, 2, 3, 1, 3, 5
Real Life Data (cont.)
 What
is the interquartile range (IQR) of this
data set? Hours of Electronics Used Per Day
Q1 =
1.25
Q3 =
3.75
Median = 2.75
Max. = 6
Min. = 1
Interquartile range: 3.75-1.25=2.5
How to Make a Box Plot
Here is an example of a set of
numbers collected.

2.5, 4.5, 4.5, 1, 1.5, 1, 3, 2, 1, 6, 3, 2, 3, 1, 3, 5
 Order the numbers
 1, 1, 1, 1, 1.5, 2, 2, 2.5, 3, 3, 3, 3, 4.5, 4.5, 5, 6
 Find the median of the set
 1, 1, 1, 1, 1.5, 2, 2, 2.5, 3, 3, 3, 3, 4.5, 4.5, 5, 6
 Q2= (2.5 + 3)/2= 2.75
How to Make a Box Plot
(cont.)
 Find
the medians of the upper and
lower quartiles
 1, 1, 1, 1, 1.5, 2, 2, 2.5 and 3, 3, 3, 3,
4.5, 4.5, 5, 6
 The median of the lower quartile is:

Q1 = (1 + 1.5)/2 = 1.25
 The median of the
 Q3 =(3 + 4.5)/2 = 3.75
upper quartile is:
How to Make a Box Plot
Hours of Electronic Used Per Day
(cont.)
Plot:
 Median = 2.75
 Q1 = 1.25
 Q3 = 3.75
 Maximum = 6
 Minimum = 1
 Draw tick marks indicating median, Q1, Q3,
minimum, and maximum
 Draw box around median, Q1, and Q3
 Connect box to maximum and minimum
endpoints to create “whiskers”

Advantages & Disadvantages
Advantages



Able to tell median,
range, lower quartile,
upper quartile,
minimum, and
maximum
Not cluttered with
too much
information
Can show outliers
Disadvantages



Doesn’t show
specific numbers
Doesn’t show subtle
changes
Can’t identify the
original numbers
used in the data set
Research Page/ Work Cited
 http://www.ck12.org/user:amhhdGVydEB
5c3NjaG9vbHMub3Jn/section/Box-andWhisker-Plots/
 http://www.purplemath.com/modules/bo
xwhisk.htm
 http://www.vertex42.com/ExcelTemplates
/box-whisker-plot.html
 http://www.edu.gov.mb.ca/k12/tech/lict/
let_me_try/g6/mh132.html
Special Thanks To…
 Jordan
Armstrong
 Chantal
 Trisha
 Mrs.
 Honors
Alano
Jiang
Ellwood
Algebra Class 