Handling Data 3
3 marks · NormalThe ages (in years) of 9 members of a chess club are:
| Age |
|---|
| 8 |
| 9 |
| 12 |
| 12 |
| 13 |
| 14 |
| 16 |
| 17 |
| 19 |
Work out the median, lower quartile, upper quartile, and inter-quartile range of these ages.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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Also accept: Quartiles at correct positions even if alternative method is shown
Common mistakes: Not placing quartile values between correct entries (use mean of values if in-between)
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Marking points
M1 · 1 mark · Ages sorted in order and correct method to find quartiles used.
A1 · 1 mark · Correct median and quartile values stated.
A2 · 1 mark · Correct value for inter-quartile range (UQ - LQ). (follow-through)
Worked solution
List ages in order: 8, 9, 12, 12, 13, 14, 16, 17, 19
Median (Q2) is the 5th value: 13
Lower half: 8, 9, 12, 12 (median between 9 and 12, so LQ = (9+12)/2 = 10.5)
Upper half: 14, 16, 17, 19 (median between 16 and 17, so UQ = (16+17)/2 = 16.5)
Inter-quartile range = 16.5 - 10.5 = 6