CAIE A-Level Mathematics 6.4.2 Sampling methods
Practise judging sampling methods, using random digits or dice fairly, and explaining when a chosen sample is biased or not random.
- Syllabus
- 2028–2030
- Course
- Mathematics 9709
- Level
- A2
Exam points
- explain why unequal chances from random numbers make a sample non-random
- use dice or random digits to allocate members with equal probability
6.4.2—Sampling methods question 1
[Maximum number: 1]
At a certain large school it was found that the proportion of students not wearing correct uniform was 0.15 . The school sent a letter to parents asking them to ensure that their children wear the correct uniform. The school now wishes to test whether the proportion not wearing correct uniform has been reduced.
It is suggested that a random sample of the students in Grade 12 should be used for the test.
Give a reason why this would not be an appropriate sample.
A suitable sample of 50 students is selected and the number not wearing correct uniform is noted. This figure is used to carry out a test at the 5\% significance level.
Not representative (of all students in the school)
B1
OE idea of 'not being representative' e.g. different grades in the school have different characteristics/proportions....
Don't accept 'not random' or 'biased' without further explanation.
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