Lesson 2.9Comparing Sets with MAD
Start hereWords, worked example, and sentence starters
Learning target I can find the mean absolute deviation (MAD) to describe how spread out data is.
Start hereWords for this lesson
Read each word before you begin. Say it out loud.
| Word | What it means | Example |
|---|---|---|
| Mean Absolute DeviationSpanish: Desviación media absoluta | The average distance of data values from the mean; it describes spread. | Written as MAD |
| DeviationSpanish: Desviación | How far a number is from the mean. | Mean 72, value 78 → 6 |
| Absolute ValueSpanish: Valor absoluto | How far a number is from zero. It is never negative. | |−3| = 3 and |3| = 3 — both are 3 units from zero |
| SpreadSpanish: Dispersión | How far apart the numbers are. | Low spread: 8, 9, 10, 11 (close together). High spread: 2, 9, 10, 25 (far apart) |
| Data distributionSpanish: Distribución de datos | How the data looks: where it sits and how spread out it is. | A set clustered tightly around the mean has low MAD; a set spread far from the mean has high MAD |
| VariabilitySpanish: Variabilidad | How spread out the numbers are. | Low variability (MAD = 1): very consistent. High variability (MAD = 8): very spread out |
How it worksWorked example
These numbers are not on your problems. The steps are. Follow them with your own numbers.
Baker A made 8, 9, 11, 12 cookies per tray. Baker B made 4, 8, 12, 16. Both means are 10. Who is steadier?
- A’s distances: 2, 1, 1, 2. MAD = 6 ÷ 4 = 1.5.
- B’s distances: 6, 2, 2, 6. MAD = 16 ÷ 4 = 4.
- 1.5 < 4, so Baker A is steadier.
Answer: Baker A
Say it and write itSentence starters
Finish each sentence out loud with a partner. Then use them in your writing.
- Both sets have a mean of .
- The MAD of is and the MAD of is .
- is more consistent because .
- A larger MAD means the values .
Word bank mean absolute deviationdeviationdistancemeanspreadvariationconsistentcomparelargersmallertypicalcenter
Watch out!A common mistake
A common mistake in Mean Absolute Deviation is adding the signed deviations (value − mean) instead of their absolute values, so the positives and negatives cancel out to 0. For 6, 8, 10, 12 (mean = 9), the deviations are −3, −1, 1, 3
Lesson 2.9Comparing Sets with MAD
Apply Day · Version ASupported practice
Learning target I can find the mean absolute deviation (MAD) to describe how spread out data is.
-
1Complete each step, then write the final answer.
Find the MAD of this data set: 1, 4, 7.
Show your workHint The mean is 4. Find how far 1, 4 and 7 are from 4.
Final answer: -
2Complete each step, then write the final answer.
Find the MAD of this data set: 5, 6, 10, 11.
Show your workHint The values add to 32. Find the mean, then each distance from it.
Final answer: -
3Complete each step, then write the final answer.
Find the MAD of this data set: 2, 4, 4, 6.
Show your workHint The mean is 4. Two values are 0 away from it.
Final answer:
Lesson 2.9Comparing Sets with MAD
Apply Day · Version BCore practice
Learning target I can find the mean absolute deviation (MAD) to describe how spread out data is.
-
1Circle the letter of the best answer. Show how you know.
Set A is 5, 6, 7. Set B is 1, 6, 11. Both sets have a mean of 6. Which set has the greater MAD?
- ASet A
- BSet B
- CThey have the same MAD
Show your work -
2Complete each step, then write the final answer.
Find the MAD of this data set: 1.5, 2.5, 3.5, 4.5.
Show your workFinal answer: -
3Complete each step, then write the final answer.
Find the MAD of this data set: 3, 7, 8, 10.
Show your workFinal answer:
Lesson 2.9Comparing Sets with MAD
Apply Day · ChallengeExtension
Learning target I can find the mean absolute deviation (MAD) to describe how spread out data is.
-
1Circle the letter of the best answer. Show how you know.
A data set is 3, 5, 9, 11 with a mean of 7. What is the mean absolute deviation?
- A2
- B3
- C7
- D28
Put the data in orderWork -
2Complete each step, then write the final answer.
Kai finds the deviations of 2, 6, 7, 9 from their mean, 6. He gets −4, 0, 1 and 3. He adds them and says the MAD is 0. What is the MAD?
Show your workFinal answer: -
3Complete each step, then write the final answer.
Find the MAD of this data set: 5, 7, 8, 10, 15.
Show your workFinal answer: