How do you describe the spread of data?

0 1 2 3 4 5

How many siblings do you have?

In this lesson you will learn how to summarize the spread of data with a single number by calculating and examining the range and mean absolute

deviation of the data.

Let’s Review

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Number of Books

How many books did 6th graders at Taylor Middle School read this summer?

Reading a line plot

A Common Mistake

Sometimes students confuse the mean and the mean absolute deviation.

Mean Mean Absolute Deviation

Center Spread

Core Lesson

Finding the Range

5-0 5

0 1 2 3 4 5

How many siblings do you have?

Core Lesson

2 + 2 + 2 + 1 + 1 + 1 + 0 + 0 + 1 + 2 + 3 + 3 = 1818 ÷ 12 = 1.5

2 222

Finding the Mean Absolute Deviation

0 1 2 3 4 5

How many siblings do you have?

0 + 0 + 0 + 1 + 1 + 1 + 2 + 2 + 3 + 4 + 5 + 5 = 2424 ÷ 12 = 2

Mean = 2

1 111

33

00

Mean Absolute Deviation = 1.5

Core Lesson

Comparing the Range and the Mean Absolute Deviation

0 1 2 3 4 5

How many siblings do you have?

Range = 5 Mean Absolute Deviation = 1.5

In this lesson you have learned how to summarize the spread of data with a single number by calculating and examining the range and mean absolute

deviation of the data.

Guided Practice

Find the range and mean absolute deviation of this data. How can we use these to describe the spread of data?

Extension Activities

Find a graph or some data in a newspaper or online. Find the range and mean absolute deviation. How do they describe the spread?

Extension Activities

Choose 2 random numbers to be the range and the mean absolute deviation. Can you write data to match these measures?

Quick Quiz

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Number of CDs owned

Find the range and mean absolute deviation of this data. How can we use these to describe the spread of data?

Quick Quiz

Find the range and mean absolute deviation of this data. How can we use these to describe the spread of data?

How many pairs of shoes do 6th graders at Wilson Junior High School own?