Sampling techniques

Overview

Sampling frames and representativeness, random, systematic, stratified, quota, opportunity and snowball sampling, and worked sampling and response rate calculations.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What is a sample, and why do sociologists use one?

   Model answer

   A sample is a smaller group chosen from the target population a sociologist wants to study. Studying everyone would usually take too long and cost too much.

2. 2

   What is a sampling frame?

   Model answer

   A sampling frame is a list of everyone in the target population, from which the sample is drawn. The Crime Survey for England and Wales draws addresses from the Royal Mail's Postcode Address File.

3. 3

   What makes a sample representative, and why does it matter?

   Model answer

   A representative sample has the same mix of characteristics as the population it comes from. Findings from such a sample can be generalised to that wider population.

4. 4

   How does random sampling work?

   Model answer

   Random sampling gives everyone in the sampling frame an equal chance of being chosen. A computer program might pick names at random from a school register.

5. 5

   Why might a random sample still be unrepresentative?

   Model answer

   Chance alone can leave some groups under-represented, such as boys or ethnic minorities. Small random samples are especially likely to be unbalanced.

6. 6

   How does systematic sampling work?

   Model answer

   Systematic sampling picks every nth name from a sampling frame, such as every tenth pupil on a register. The first name is chosen at random to avoid researcher bias.

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