# Box & Whisker Plot - PowerPoint PPT Presentation

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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).

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Box & Whisker Plot

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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)

• 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.)

• 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 