Stage 8 - Q1 - 2 marks
A factory checks 24 of its 600 new lamps. Identify the population.
Hint
The population is the full group about which a conclusion is wanted.
Stage 8 - Q2 - 2 marks
A librarian questions 18 readers out of 270 registered readers. Identify the sample.
Hint
The sample consists of those actually observed or asked.
Stage 8 - Q3 - 2 marks
Give one advantage of sampling instead of a census of 5000 visitors.
Hint
Compare the amount of collection work involved.
Stage 8 - Q4 - 2 marks
A school asks only chess-club members about a new sport. Explain the selection problem.
Hint
Who is excluded by the selection rule?
Stage 8 - Q5 - 3 marks
Describe how to select 15 different people at random from a numbered list of 150.
Hint
A full list and a random process are both needed.
Stage 8 - Q6 - 3 marks
A sample of 40 has 16 Year 8 and 24 Year 9 pupils. The two year groups have equal size. Explain one concern.
Hint
Compare sample proportions with population proportions.
Stage 8 - Q7 - 3 marks
Every fifth visitor is sampled, beginning with visitor 3. List the first six selected positions.
Hint
Keep the same interval after the starting position.
Stage 8 - Q8 - 3 marks
A public survey has 1000 responses, all from one social-media page. Is the large size enough for a representative sample?
Hint
Think about who could never be selected.
Stage 8 - Q9 - 3 marks
A manager chooses 10 visitors at each of five times. State a strength and a remaining limitation.
Hint
Improving one part of a design does not remove every source of bias.
Stage 8 - Q10 - 5 marks
Challenge: two library surveys disagree. One asks 60 morning visitors; the other asks 30 visitors across mornings and evenings. Which is more informative about all visitors? Explain what else you need.
Hint
Separate sample size, coverage and selection method.