How do you determine which team played more consistently over the last six years?

In this lesson you will learn how to informally compare two populations by using the range

and interquartile range.

Let’s ReviewLet’s Review

Range : The difference between the greatest number and lowest number

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Range

Range= 114 – 66=48

Let’s ReviewLet’s Review

Interquartile Range (IQR): The range of the middle of the data. The difference between the upper quartile and lower quartile.

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IQR

IQR = 94 – 76 = 18

Let’s ReviewA Common Mistake

Finding the lower (Q1) and upper (Q3) quartiles

16 18 19 19 20 20 23 28 30

Q2=20Q1=18.5 Q3=25.5

Let’s ReviewCore Lesson

Measures of VariabilityRange, Interquartile Range, Median Absolute Deviation

Range – influenced by outliersIQR – not influenced by outliers

Let’s ReviewCore Lesson

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Flamingos

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Cougars

Number of Team Wins (6 seasons)

Range = 51-31=20 IQR = 47-31=16

Range = 42-36=6 IQR = 42-39=3

Let’s ReviewCore Lesson

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NFC

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Number of Team Penalties (NFL)

Range = 138-60=78 IQR = 113-68=45

Range = 114-66=48 IQR = 94-76=18

In this lesson you have learned how to informally compare two populations by using the range

and interquartile range.

Let’s ReviewGuided Practice

Compare the range and IQR of the medal count at the Summer Olympics for 1992 – 2008.

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60 65 70 75 80 85 90 95 100 105 110 115

USA

Russia

Let’s ReviewExtension Activities

Go to www.databaseOlympics.com, choose a range of years, and pick 2 countries. Find the medal count for the Winter Olympics for each of those countries. Use the range and IQR to compare the medal count for each country.

Let’s ReviewExtension Activities

Measure the arm span and height of 7 classmates. Compare the two by using the range and IQR of each measurement.

Let’s ReviewQuick Quiz

Compare the range and IQR to determine which week the fitness club exercised the least.

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30 35 40 45 50 55 60 65 70 75 80 85 90

Week 1

Week 2

Let’s ReviewQuick Quiz

Use the range and IQR to determine who trained more for the marathon last week.

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1 2 3 4 5 6 7 8 9 10 11 12

Lucy

Debra