MathIQO worksheet
Determine quartiles and the interquartile range · Grade 9 · D1.2
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Date: ______________________
- 1
These values are already in order. Find the interquartile range (IQR): 12, 16, 19, 21, 24, 27, 31.
Warm-upAnswer:
- 2
These values are already in order. Find the interquartile range (IQR): 11, 13, 15, 17, 18, 22, 26.
Warm-upAnswer:
- 3
These values are already in order. Find the interquartile range (IQR): 7, 10, 11, 13, 18, 20, 22.
Warm-upAnswer:
- 4
Find the interquartile range (IQR) of this data set: 9, 12, 23, 3, 16, 18, 7.
On levelAnswer:
- 5
Find the interquartile range (IQR) of this data set: 15, 23, 13, 20, 22, 8, 4.
On levelAnswer:
- 6
Find the interquartile range (IQR) of this data set: 16, 10, 14, 19, 4, 6, 3.
On levelAnswer:
- 7
Find the interquartile range (IQR) of this data set: 41, 35, 28, 17, 6, 30, 21, 40, 12, 25, 8.
ChallengeAnswer:
- 8
Find the interquartile range (IQR) of this data set: 34, 36, 13, 22, 25, 10, 30, 5, 17, 35, 38.
ChallengeAnswer:
- 9
Find the interquartile range (IQR) of this data set: 46, 31, 18, 45, 22, 39, 29, 36, 28, 23, 41.
ChallengeAnswer:
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Answer key · Determine quartiles and the interquartile range
- 1.11 — Lower half 12, 16, 19 → Q1 = 16; upper half 24, 27, 31 → Q3 = 27. IQR = 27 − 16 = 11.
- 2.9 — Lower half 11, 13, 15 → Q1 = 13; upper half 18, 22, 26 → Q3 = 22. IQR = 22 − 13 = 9.
- 3.10 — Lower half 7, 10, 11 → Q1 = 10; upper half 18, 20, 22 → Q3 = 20. IQR = 20 − 10 = 10.
- 4.11 — In order: 3, 7, 9, 12, 16, 18, 23. Q1 = 7, Q3 = 18, so IQR = 18 − 7 = 11.
- 5.14 — In order: 4, 8, 13, 15, 20, 22, 23. Q1 = 8, Q3 = 22, so IQR = 22 − 8 = 14.
- 6.12 — In order: 3, 4, 6, 10, 14, 16, 19. Q1 = 4, Q3 = 16, so IQR = 16 − 4 = 12.
- 7.23 — In order: 6, 8, 12, 17, 21, 25, 28, 30, 35, 40, 41. With 11 values, Q1 = 12 and Q3 = 35, so IQR = 35 − 12 = 23.
- 8.22 — In order: 5, 10, 13, 17, 22, 25, 30, 34, 35, 36, 38. With 11 values, Q1 = 13 and Q3 = 35, so IQR = 35 − 13 = 22.
- 9.18 — In order: 18, 22, 23, 28, 29, 31, 36, 39, 41, 45, 46. With 11 values, Q1 = 23 and Q3 = 41, so IQR = 41 − 23 = 18.