Mean Absolute Deviation (MAD)

Mean Absolute Deviation (MAD)

SWBAT calculate the average distance from the mean.

Things you will need for today's lesson

• Calculator

• Pencil

• Paper

LET'S RECAP

What is the process for calculating the mean?

Multiple Choice

How do you calculate the Mean (average)?

• Finding the middle number

• adding all numbers up and dividing by how many numbers there are.

• Subtracting the greatest value from the least value number in the data set.

• Finding what number occurs the most.

Multiple Choice

What is the average (mean) of these five numbers?

3 ,7 ,1 ,6 ,8

• 1

• 6

• 5

• 8

Multiple Choice

What is the mean (average)?

10, 20, 30, 40, 50, 60, 70

• 30

• 40

• 50

Absolute Value

How far an integer is from zero regardless of the sign.

Multiple Choice

How far is the number five from zero?

• 0

• 5

• 3

Multiple Choice

How far is negative five (-5) from zero on a number line?

• 0

• 1

• 5

• -5

Let's watch a video to learn how to find Mean Absolute Deviation (MAD)

https://www.youtube.com/watch?v=ytUj53rYCME

Why is it important to find the M.A.D of a data set?

• Think about our last test... What was your grade? What was the class average?

• How far away from the class average was your score? How far away from the class average was everyone else?

To find mean absolute deviation:

• Calculate the mean of the set .                         

• Find the distance that each number in the set is from the mean and write the differences (deviations) in a list.                     

• *NOTE- This value needs to be positive because it is the absolute value of the deviation. It does not matter if the values are above or below the mean. This distance will always be positive.   

• Calculate the mean of the deviations.

An example: Find the mean standard deviation of this number set -  4, 9, 12

• Step 1- Find the mean of the number set

• Step 2- Go through each number and find how far away each one is from the mean by subtracting. List them. This is called deviation.

• Step 3- Take the mean of the deviations (add up all of the deviation values and divided by how many numbers you added.

• Answer- Approximately 2.87

Multiple Choice

What is the first step when calculating the Mean Absolute Deviation?

• Find the distance each value is from the mean

• Find the mean of the distances

• Find the mean of the data

Multiple Choice

What is the second step when calculating the Mean Absolute Deviation?

• Find the distance each value is from the mean

• Find the mean of the distances

• Find the mean of the data

Multiple Choice

What is the third step when calculating the Mean Absolute Deviation?

• Find the distance each value is from the mean

• Find the mean of the distances

• Find the mean of the data

Multiple Choice

Find the Mean Absolute Deviation: (MAD)

10, 9, 3, 8, 10.

• 3

• 1.5

• 5.0

• 2