Grade 9 Data Handling Quiz 2 draws its questions at random from 29 questions across these topics:
A few of the question types, with full solutions, so you know what to expect.
Collecting data. A school has 480 Grade 9 learners. A teacher surveys 60 of them. Which statement is correct?
Answer: The population is 480 and the sample is 60
The POPULATION is the entire group being studied.
The SAMPLE is the smaller group actually asked.
All 480 Grade 9 learners form the population; the 60 asked form the sample.
Collecting data. A learner wants the most popular music genre among Grade 9s, but asks only the 10 friends in her friend group. Which sampling method is this?
Answer: Convenience sampling
She chose the people who were easiest for her to reach.
That is the definition of convenience sampling.
Tip: In the exam you must also EXPLAIN the bias: friends tend to share tastes, so the group does not represent the whole grade.
Collecting data. A school has 900 learners. A researcher wants a systematic sample of 45. What interval should she use?
Answer: Every 20th learner
The interval is the population divided by the sample size.
900 ÷ 45 = 20
Collecting data. Which of these is a STATISTICAL question?
Answer: How long does it take learners to get to school?
A statistical question is answered by collecting data that VARIES between people.
Travel time differs from learner to learner, so it produces a data set.
The other three each have one fixed correct answer.
Collecting data. Which sampling method gives every member of the population an EQUAL chance of being chosen?
Answer: Random sampling
Random sampling means no member is favoured — for example names drawn from a hat.
Systematic sampling follows a fixed interval, so it is not equal-chance in the same sense.