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): 1, 6, 10, 14, 19, 20, 23.
Warm-upAnswer:
- 2
These values are already in order. Find the interquartile range (IQR): 12, 16, 18, 21, 24, 28, 29.
Warm-upAnswer:
- 3
These values are already in order. Find the interquartile range (IQR): 11, 13, 16, 19, 20, 23, 27.
Warm-upAnswer:
- 4
Find the interquartile range (IQR) of this data set: 17, 14, 28, 22, 31, 24, 12.
On levelAnswer:
- 5
Find the interquartile range (IQR) of this data set: 12, 26, 10, 23, 20, 7, 16.
On levelAnswer:
- 6
Find the interquartile range (IQR) of this data set: 35, 20, 13, 24, 17, 31, 26.
On levelAnswer:
- 7
Find the interquartile range (IQR) of this data set: 17, 3, 30, 15, 40, 7, 10, 35, 26, 22, 39.
ChallengeAnswer:
- 8
Find the interquartile range (IQR) of this data set: 32, 20, 26, 36, 40, 53, 47, 52, 24, 30, 42.
ChallengeAnswer:
- 9
Find the interquartile range (IQR) of this data set: 15, 20, 49, 25, 37, 23, 34, 44, 29, 41, 10.
ChallengeAnswer:
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Answer key · Determine quartiles and the interquartile range
- 1.14 — Lower half 1, 6, 10 → Q1 = 6; upper half 19, 20, 23 → Q3 = 20. IQR = 20 − 6 = 14.
- 2.12 — Lower half 12, 16, 18 → Q1 = 16; upper half 24, 28, 29 → Q3 = 28. IQR = 28 − 16 = 12.
- 3.10 — Lower half 11, 13, 16 → Q1 = 13; upper half 20, 23, 27 → Q3 = 23. IQR = 23 − 13 = 10.
- 4.14 — In order: 12, 14, 17, 22, 24, 28, 31. Q1 = 14, Q3 = 28, so IQR = 28 − 14 = 14.
- 5.13 — In order: 7, 10, 12, 16, 20, 23, 26. Q1 = 10, Q3 = 23, so IQR = 23 − 10 = 13.
- 6.14 — In order: 13, 17, 20, 24, 26, 31, 35. Q1 = 17, Q3 = 31, so IQR = 31 − 17 = 14.
- 7.25 — In order: 3, 7, 10, 15, 17, 22, 26, 30, 35, 39, 40. With 11 values, Q1 = 10 and Q3 = 35, so IQR = 35 − 10 = 25.
- 8.21 — In order: 20, 24, 26, 30, 32, 36, 40, 42, 47, 52, 53. With 11 values, Q1 = 26 and Q3 = 47, so IQR = 47 − 26 = 21.
- 9.21 — In order: 10, 15, 20, 23, 25, 29, 34, 37, 41, 44, 49. With 11 values, Q1 = 20 and Q3 = 41, so IQR = 41 − 20 = 21.