Representative samples — Sociology, 14–17 years
Learn how researchers can study a large population by carefully choosing a smaller group. Sociology, 14–17 years.
Idea
A sample is a smaller group chosen to tell us something about a larger population. It is representative when important features of that population are reflected in roughly the right proportions, so the answers are not just the opinions of whoever happened to reply.
Why it matters
Asking every person in a country is usually too slow, expensive or impossible, so surveys use samples. Sampling became central to modern social research because a carefully selected few can estimate a wider pattern, while a badly selected few can produce a confident but misleading result.
Worked example
A school has 1,000 students: 600 are girls and 400 are boys. To survey 100 students, a researcher first keeps that 60:40 balance, selecting 60 girls and 40 boys at random from the registers. If 30 girls and 10 boys choose cycling, the estimate is 40% of the school.
A common trap
The trap is believing that a large sample is automatically a good sample. It feels sensible because more answers seem stronger, but 10,000 replies from one fan club may represent that club very well and the whole population very badly; selection matters as much as size.
Where it appears
Election polls, health surveys, consumer research and school questionnaires all use samples. When reading a result, ask who was included, who was missed, how people were chosen and how many answered; those details tell you how far the claim can travel.
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