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Determine quartiles and the interquartile range · Grade 9 · D1.2

Name: ______________________

Date: ______________________

  1. 1

    These values are already in order. Find the interquartile range (IQR): 12, 17, 22, 24, 29, 30, 31.

    Warm-up

    Answer:

  2. 2

    These values are already in order. Find the interquartile range (IQR): 12, 13, 17, 22, 23, 24, 26.

    Warm-up

    Answer:

  3. 3

    These values are already in order. Find the interquartile range (IQR): 2, 4, 9, 14, 15, 19, 24.

    Warm-up

    Answer:

  4. 4

    Find the interquartile range (IQR) of this data set: 21, 9, 13, 12, 2, 17, 4.

    On level

    Answer:

  5. 5

    Find the interquartile range (IQR) of this data set: 1, 23, 9, 19, 13, 14, 6.

    On level

    Answer:

  6. 6

    Find the interquartile range (IQR) of this data set: 14, 31, 24, 13, 26, 15, 19.

    On level

    Answer:

  7. 7

    Find the interquartile range (IQR) of this data set: 30, 8, 21, 10, 12, 11, 31, 17, 5, 25, 22.

    Challenge

    Answer:

  8. 8

    Find the interquartile range (IQR) of this data set: 10, 5, 6, 15, 20, 11, 21, 4, 9, 8, 19.

    Challenge

    Answer:

  9. 9

    Find the interquartile range (IQR) of this data set: 36, 10, 35, 15, 24, 27, 18, 30, 20, 19, 5.

    Challenge

    Answer:

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Worksheet code: eyJzIjoiZGF0YS1pcXIiLCJkIjpbOTQwNDQzMzg5LDE0NDgzMTQzNTYsNzQyNzA2NzYsMzE2NzEzMDg5LDEyNjIxMDk4ODIsMTQ1MTcxMTAwNiwxODYyNjU0NjkyLDEzMjgyNDk1NiwyMTA4MDQ0MzI5XSwidiI6MX0.1fc39b7588b2

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Answer key · Determine quartiles and the interquartile range

  1. 1.
    13 — Lower half 12, 17, 22 → Q1 = 17; upper half 29, 30, 31 → Q3 = 30. IQR = 30 − 17 = 13.
  2. 2.
    11 — Lower half 12, 13, 17 → Q1 = 13; upper half 23, 24, 26 → Q3 = 24. IQR = 24 − 13 = 11.
  3. 3.
    15 — Lower half 2, 4, 9 → Q1 = 4; upper half 15, 19, 24 → Q3 = 19. IQR = 19 − 4 = 15.
  4. 4.
    13 — In order: 2, 4, 9, 12, 13, 17, 21. Q1 = 4, Q3 = 17, so IQR = 17 − 4 = 13.
  5. 5.
    13 — In order: 1, 6, 9, 13, 14, 19, 23. Q1 = 6, Q3 = 19, so IQR = 19 − 6 = 13.
  6. 6.
    12 — In order: 13, 14, 15, 19, 24, 26, 31. Q1 = 14, Q3 = 26, so IQR = 26 − 14 = 12.
  7. 7.
    15 — In order: 5, 8, 10, 11, 12, 17, 21, 22, 25, 30, 31. With 11 values, Q1 = 10 and Q3 = 25, so IQR = 25 − 10 = 15.
  8. 8.
    13 — In order: 4, 5, 6, 8, 9, 10, 11, 15, 19, 20, 21. With 11 values, Q1 = 6 and Q3 = 19, so IQR = 19 − 6 = 13.
  9. 9.
    15 — In order: 5, 10, 15, 18, 19, 20, 24, 27, 30, 35, 36. With 11 values, Q1 = 15 and Q3 = 30, so IQR = 30 − 15 = 15.