MathIQO worksheet
Determine quartiles and the interquartile range · Grade 9 · D1.2
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- 1
These values are already in order. Find the interquartile range (IQR): 8, 13, 16, 18, 20, 24, 28.
Warm-upAnswer:
- 2
These values are already in order. Find the interquartile range (IQR): 12, 17, 20, 24, 25, 27, 31.
Warm-upAnswer:
- 3
These values are already in order. Find the interquartile range (IQR): 8, 13, 14, 19, 21, 25, 29.
Warm-upAnswer:
- 4
Find the interquartile range (IQR) of this data set: 20, 5, 22, 13, 12, 16, 8.
On levelAnswer:
- 5
Find the interquartile range (IQR) of this data set: 10, 25, 19, 21, 16, 11, 30.
On levelAnswer:
- 6
Find the interquartile range (IQR) of this data set: 22, 8, 32, 10, 27, 14, 18.
On levelAnswer:
- 7
Find the interquartile range (IQR) of this data set: 18, 23, 16, 13, 41, 36, 38, 33, 25, 28, 20.
ChallengeAnswer:
- 8
Find the interquartile range (IQR) of this data set: 17, 8, 30, 20, 18, 19, 24, 26, 15, 33, 10.
ChallengeAnswer:
- 9
Find the interquartile range (IQR) of this data set: 26, 6, 25, 3, 30, 17, 8, 12, 18, 11, 20.
ChallengeAnswer:
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Answer key · Determine quartiles and the interquartile range
- 1.11 — Lower half 8, 13, 16 → Q1 = 13; upper half 20, 24, 28 → Q3 = 24. IQR = 24 − 13 = 11.
- 2.10 — Lower half 12, 17, 20 → Q1 = 17; upper half 25, 27, 31 → Q3 = 27. IQR = 27 − 17 = 10.
- 3.12 — Lower half 8, 13, 14 → Q1 = 13; upper half 21, 25, 29 → Q3 = 25. IQR = 25 − 13 = 12.
- 4.12 — In order: 5, 8, 12, 13, 16, 20, 22. Q1 = 8, Q3 = 20, so IQR = 20 − 8 = 12.
- 5.14 — In order: 10, 11, 16, 19, 21, 25, 30. Q1 = 11, Q3 = 25, so IQR = 25 − 11 = 14.
- 6.17 — In order: 8, 10, 14, 18, 22, 27, 32. Q1 = 10, Q3 = 27, so IQR = 27 − 10 = 17.
- 7.18 — In order: 13, 16, 18, 20, 23, 25, 28, 33, 36, 38, 41. With 11 values, Q1 = 18 and Q3 = 36, so IQR = 36 − 18 = 18.
- 8.11 — In order: 8, 10, 15, 17, 18, 19, 20, 24, 26, 30, 33. With 11 values, Q1 = 15 and Q3 = 26, so IQR = 26 − 15 = 11.
- 9.17 — In order: 3, 6, 8, 11, 12, 17, 18, 20, 25, 26, 30. With 11 values, Q1 = 8 and Q3 = 25, so IQR = 25 − 8 = 17.