Unit 7 · Data and Percentage
School Exam Results — Analyse the Data
Lesson 2 of 3
Two tables, one prize. The trap in this question is that the Year 10 table is sorted by final score — so the student at the top looks like the obvious winner. But the prize is for biggest IMPROVEMENT, not highest score. Always re-read the rule before looking at the data, or you will answer a completely different question to the one being asked.
Two-table comparison questions where you must compute a derived value (difference, ratio, percentage change) appear regularly in OC TS data questions. The examiner always sorts or presents one table in a way that tempts you to pick the wrong answer — highest score, most recent result, etc. — instead of applying the actual stated rule.
The examiner is checking two things: (1) that you read and apply the correct rule (biggest improvement, not highest score), and (2) that you perform the subtraction for EVERY student before comparing — not just the ones who appear most impressive at a glance.
Two tables of the same group of people across two time points are given. A selection rule is stated (e.g. "biggest improvement", "highest percentage increase"). You must compute the relevant value for each person, rank them, and identify the winner. The order of one table will be misleading.
Best approach: Make a third column in your working. Write each student's name, then Year 9 mark, then Year 10 mark, then calculate the difference (Year 10 minus Year 9) for each one. Rank those differences — the largest positive difference is the winner. Never try to eyeball the improvement from two separate tables; always write the subtraction out for every student.
Question
At a school, exams are held at the end of each year. A prize is awarded in each subject to the student who has made the biggest improvement in his/her exam mark since the previous year. In Year 9, the marks achieved by the six students in the Mathematics class were as follows:
| Student | Year 9 mark |
|---|---|
| Uma | 84 |
| Finn | 82 |
| Lily | 75 |
| Arlo | 73 |
| Leon | 73 |
| Sophie | 69 |
At the end of Year 10, their marks were as follows:
| Student | Year 10 mark |
|---|---|
| Finn | 88 |
| Lily | 86 |
| Uma | 79 |
| Arlo | 78 |
| Sophie | 78 |
| Leon | 73 |
Which student won the Year 10 prize for Mathematics?
Select an answer to see the explanation.
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