CAPS · Grade 8 · K
Two methods are suggested to select 6 households in a suburb for a water-usage survey. Method A: A researcher only visits the households on one street corner. Method B: Every one of the 702 households is given a number, and a computer randomly selects 6 numbers. Which method is RANDOM sampling? Give a reason.
Two methods are suggested to test 24 tins from a production batch of 4878 tins for a factory quality check. Method A: The quality inspector only tests the 24 tins packed last, at the end of the shift. Method B: A computer randomly selects 24 tin numbers from the whole batch. Which method is RANDOM sampling? Give a reason.
A researcher wants to know the average screen time of the 1200 learners at a high school in Polokwane. She surveys 32 learners waiting outside the hall. Identify the population and the sample in this investigation.
A school wants Grade 8 opinions on the tuck shop menu. Every Grade 8 learner's name is entered into a computer, which randomly selects 27 of them. Is this a biased sample or a fair (representative) sample? Give a reason.
Two methods are suggested to choose 8 apples from a crate of 279 to check for bruising. Method A: An inspector uses a random-number generator to pick 8 crate positions. Method B: An inspector only checks the 8 apples on the very top of the crate. Which method is RANDOM sampling? Give a reason.
A teacher wants the average shoe size of a class of 32 learners. Names are drawn one at a time out of a hat containing every learner's name. Is this a biased sample or a fair (representative) sample? Give a reason.
Two methods are suggested to select 6 learners from a class of 32 to interview about homework. Method A: The teacher picks the learners who always sit in the front row. Method B: The teacher writes all 32 names on paper, mixes them in a box, and draws out 6. Which method is RANDOM sampling? Give a reason.
To check the quality of a batch of 1646 light bulbs, a factory worker tests every 15th bulb off the production line. Is this a biased sample or a fair (representative) sample? Give a reason.
Two methods are suggested to choose 8 apples from a crate of 193 to check for bruising. Method A: An inspector uses a random-number generator to pick 8 crate positions. Method B: An inspector only checks the 8 apples on the very top of the crate. Which method is RANDOM sampling? Give a reason.
A council in Tzaneen wants residents' views on a new park. Survey forms are left in the library for anyone to fill in and return — 37 are returned. Is this a biased sample or a fair (representative) sample? Give a reason.
A school wants to know learners' favourite sport. The principal only asks the 17 members of the first-team rugby squad. Is this a biased sample or a fair (representative) sample? Give a reason.
A quality inspector wants to know the average lifespan of a batch of 2824 light bulbs. He tests 71 bulbs picked at random from the batch. Identify the population and the sample in this investigation.