Box & Whisker Plot

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# Box & Whisker Plot - PowerPoint PPT Presentation

Box &amp; Whisker Plot. Chantal Alano, Trisha Jiang, Jordan Armstrong Period 1. What is a Box &amp; 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).

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### 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)
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.)
• Whatis 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 and3, 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 upper quartile is:
• Q3 =(3 + 4.5)/2 = 3.75
How to Make a Box Plot (cont.)

Hours of Electronic Used Per Day

• 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”

Doesn’t show specific numbers

Doesn’t show subtle changes

Can’t identify the original numbers used in the data set

• Able to tell median, range, lower quartile, upper quartile, minimum, and maximum
• Not cluttered with too much information
• Can show outliers
Research Page/ Work Cited
• http://www.ck12.org/user:amhhdGVydEB5c3NjaG9vbHMub3Jn/section/Box-and-Whisker-Plots/
• http://www.purplemath.com/modules/boxwhisk.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 Alano
• Trisha Jiang
• Mrs. Ellwood
• Honors Algebra Class 