Start here

You did these with your group. Now do them on your own — the model above is yours to copy.

1. 1

   Same stepsFinish what the group started. Use the model above, step for step.

   Let's do one together: Class A's box plot shows: least 62, Q1 74, median 81, Q3 87, greatest 90. Find the range and the IQR. Find the range: greatest − least. (90 − 62 = 28) Find the IQR: Q3 − Q1. (87 − 74 = 13) What does each number tell you? (All the scores spread over 28 points. The middle half spreads over only 13 points.)

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

   Show your work
2. 2

   Warm restartA box plot has minimum 4, Q1 = 7, median = 10, Q3 = 14 and maximum 20. Which value splits the data in half?

   1. A7
   2. B10
   3. C12
   4. D14
3. 3

   Warm restartIn that same box plot, what does the LEFT edge of the box show?

   1. AQ1, which is 7
   2. BQ3, which is 14
   3. CThe minimum, which is 4
   4. DThe median, which is 10
4. 4

   Warm restartFind the five-number summary of 2, 5, 6, 8, 9, 11, 14.

   1. A2, 5, 8, 11, 14
   2. B2, 6, 8, 9, 14
   3. C2, 5, 6, 11, 14
   4. D2, 8, 11, 14, 14

You answered these out loud. Now write them.

Answer, then say how you know — the reason is the part that counts.

1. 5

   Think it throughWhat is the range of Class A's scores?

   1. A13 points
   2. B28 points
   3. C81 points
   4. D90 points

   Why is that the answer?

   I chose ___ because ___ .
2. 6

   Think it throughWhat is the interquartile range of Class B's scores?

   1. A8 points
   2. B14 points
   3. C20 points
   4. D81 points

   How do you know?

   I chose ___ because ___ .
3. 7

   Think it throughBoth classes have a median of 81. What do the smaller range and smaller IQR tell you about Class B?

   1. AClass B's best score was higher
   2. BClass B had fewer students
   3. CClass B's median is actually larger
   4. DClass B's scores are less spread out, so more students scored near the median

   Explain your thinking.

   I chose ___ because ___ .
4. 8

   Back to the modelBoth numbers describe spread. Why might a coach trust the IQR more than the range when one player had a record-breaking night?

   I would use the ___ because it only uses the ___, so one unusual value cannot ___.

Sort it again — on paper this time

Write the letter of the group each one belongs in.

• 94 − 68 = 26
• 88 − 75.5 = 12.5
• Uses the greatest and least values
• Uses the third quartile and the first quartile
• Describes the middle half of the data
• Describes every value in the data set
• The width of the box on a box plot
• One unusually high value stretches it a lot

Use the words

Fill each blank with a word from the bank.

• The range uses the ___ values; the interquartile range uses the ___.
• Subtract the least value from the ___ value to find the range.
• Numbers that split ordered data into four equal parts are ___.
• The spread of the middle half of the data, Q3 − Q1, is the ___ ___.

Explain the thinking

1. 9

   Find the mistakeAnother student made this exact mistake in this lesson. Explain why it is wrong, then write what they should have done.

   The mistake: A common mistake with Range and Interquartile Range is adding the two quartiles instead of subtracting them — writing IQR = Q3 + Q1.
2. 10

   Say moreWhy does the range change a lot when one unusual value is added, but the IQR barely moves?

   The range uses the ___ and ___ values, so one unusual value ___ it.
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.

   If ___ changed to ___ , then ___ .

   Show your work

Last check

These two come from Lesson 2.4. If they are shaky, that is the lesson to revisit — not this one.

1. 12

   Show what you knowQuick check — you've got this: A box plot has Q1 = 20 and Q3 = 36, with a least value of 10 and a greatest value of 50. What is the IQR, and what does it tell you?

   1. AIQR = 16; the middle half of the data spans 16 units
   2. BIQR = 28; 28 is halfway between the quartiles
   3. CIQR = 40; the data spans 40 units from end to end
   4. DIQR = 56; the quartiles add to 56

   Explain your choice.

   I know it is ___ because ___ .
2. 13

   From Lesson 2.4Quick check — you've got this: A box plot has Q1 = 20 and Q3 = 36. What is the IQR and what does it represent?

   1. AIQR = 16; it is the spread of the middle 50% of the data
   2. BIQR = 28; it is the median between Q1 and Q3
   3. CIQR = 36; it is the value of Q3
   4. DIQR = 56; it is the total of Q1 and Q3
3. 14

   From Lesson 2.4Is the fan right that Team B is better because of the 80-point game?

   1. AYes — 80 is the highest score in the data
   2. BNo — Team A's maximum is higher
   3. CYes — the maximum always decides
   4. DNo — one high game is a single extreme value, not typical performance

Be honest — this tells your teacher what to do next