Start here

Use the model to solve the first problem. Then try these quick review questions from earlier lessons.

1. 1

   Same stepsFinish what the group started. Use the model above, step for step. 🔊 Listen 💡 Hint

   Let's do one together:

   1. Find the MAD of this data set: 9, 10, 11.
   2. Add the three values and divide by 3. What is the mean? (9 + 10 + 11 = 30, and 30 ÷ 3 = 10)
   3. How far is each value from 10? (9 is 1 away, 10 is 0 away and 11 is 1 away.)
   4. Add the distances and divide by 3. What is the MAD? ((1 + 0 + 1) ÷ 3 = 2/3)
   5. Is this MAD small or large? What does it tell us? (Small. The values are close together.)

   My first step is ___ , because the problem asks for ___ .

   Show your work
2. 2

   Quick reviewFind the mean of 10, 14, 8, 12 and 16. 🔊 Listen 💡 Hint

   1. A10
   2. B12
   3. C14
   4. D60
3. 3

   Quick reviewFour friends have 6, 9, 4 and 5 stickers. If they share them equally, how many does each get? 🔊 Listen 💡 Hint

   1. A4
   2. B5
   3. C6
   4. D24
4. 4

   Quick reviewA student's first three quiz scores are 82, 90 and 86. What score on a fourth quiz gives a mean of 87? 🔊 Listen 💡 Hint

   1. A86
   2. B88
   3. C90
   4. D92

Try these on your own

Choose an answer. Then explain how you know.

1. 5

   Think it throughWhat is each keeper's mean goals allowed per game? 🔊 Listen 💡 Hint

   1. Aabout 1.67
   2. B2
   3. C6
   4. D10

   Why is that the answer?

   I chose ___ because ___ .
2. 6

   Think it throughWhat does a smaller MAD tell you? 🔊 Listen 💡 Hint

   1. AThe values stay closer to the mean — the keeper is more consistent
   2. BThe keeper allowed fewer goals overall
   3. CThe keeper played fewer games
   4. DThe mean is wrong

   How do you know?

   I chose ___ because ___ .
3. 7

   Think it throughWhich keeper should the coach start, and why? 🔊 Listen 💡 Hint

   1. AKeeper B, because two shutouts is best
   2. BEither one, because the means are equal
   3. CKeeper A, because the smaller MAD (0.67) means more consistent performance
   4. DKeeper B, because a larger MAD means more skill

   Explain your thinking.

   I chose ___ because ___ .
4. 8

   Back to the modelPlayer A's MAD is 2.4 points. If Player B's MAD is 7.2 points, what does that tell you about their consistency? 🔊 Listen 💡 Hint

   Player A has a ___ MAD, which means their scores are ___ to the mean. Player B has a ___ MAD, which means their scores are ___ from the mean. The more consistent player is ___ because ___.

Use the words

Fill each blank with a word from the bank.

• The average distance of each value from the mean is the ___.
• How far a single value is from the mean is its ___.
• The distance of a number from zero, never negative (zero is allowed), is its ___.
• How far apart the data values are from each other is the ___.

Explain the thinking

1. 9

   Find the mistakeRead the mistake. Explain what went wrong, then show the correct step. 🔊 Listen 💡 Hint

   The 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.
2. 10

   Say moreTo find the MAD for Player A (18, 22, 20, 24, 16, mean 20), why do we take the ABSOLUTE VALUE of each deviation before averaging? 🔊 Listen 💡 Hint

   We use absolute value so the deviations are all ___.
3. 11

   Change one numberGo back to Part 1 and pick one problem you already solved. Change one number in it, then solve your new version. Show every step. 🔊 Listen 💡 Hint

   If ___ changed to ___ , then ___ .

   Show your work

Last check

These two come from Lesson 2.8. If they are shaky, that is the lesson to revisit — not this one.

1. 12

   Show what you knowQuick check — you've got this: Data set: 4, 8, 6, 10, 2. The mean is 6. What is the MAD? 🔊 Listen 💡 Hint

   1. A0
   2. B2.4
   3. C6
   4. D12

   Explain your choice.

   I know it is ___ because ___ .
2. 13

   From Lesson 2.8Quick check — you've got this: Data set: 8, 12, 10, 14. What is the mean? 🔊 Listen 💡 Hint

   1. A10
   2. B11
   3. C12
   4. D44
3. 14

   From Lesson 2.8Her nine games total 13 points below the target mean and 11 points above it. What must game 10 be for the data to balance at 15? 🔊 Listen 💡 Hint

   1. A13 points — 2 below the target mean
   2. B15 points — exactly the target mean
   3. C17 points — 2 above the target mean
   4. D24 points — enough to double the points above

Check your progress

Choose the box that best describes how you feel about each skill.