| Date | May 2012 | Marks available | 1 | Reference code | 12M.2.hl.TZ1.5 |
| Level | HL only | Paper | 2 | Time zone | TZ1 |
| Command term | How many | Question number | 5 | Adapted from | N/A |
Question
The box and whisker plot below illustrates the IB grades obtained by 100 students.
IB grades can only take integer values.
How many students obtained a grade of more than 4?
State, with reasons, the maximum possible number and minimum possible number of students who obtained a 4 in the exam.
Markscheme
50 A1
[1 mark]
Lower quartile is 4 so at least 26 obtained a 4 R1
Lower bound is 26 A1
Minimum is 2 but the rest could be 4 R1
So upper bound is 49 A1
Note: Do not allow follow through for A marks.
Note: If answers are incorrect award R0A0; if argument is correct but no clear lower/upper bound is stated award R1A0; award R0A1 for correct answer without explanation or incorrect explanation.
[4 marks]
Examiners report
Very few candidates were successful in answering this question. In many cases it was clear that candidates were not familiar with box-and-whisker plots at all; in other cases the explanations given revealed various misconceptions.
Very few candidates were successful in answering this question. In many cases it was clear that candidates were not familiar with box-and-whisker plots at all; in other cases the explanations given revealed various misconceptions.
