Sampling and ethical guidelines

Overview

Target populations, representative samples and generalisability, random, opportunity and self-selected sampling, and the British Psychological Society's ethical guidelines.

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 the difference between a target population and a sample?

   Model answer

   The target population is the whole group of people a researcher wants to find out about. A sample is the smaller group selected from it to take part.

2. 2

   What does it mean for a sample to be representative?

   Model answer

   A representative sample has the same characteristics as its target population, such as a similar mix of ages and genders. Results from a representative sample reflect the whole population.

3. 3

   What is generalisability?

   Model answer

   Generalisability is how far the findings from a sample can be applied to the whole target population. A representative sample makes results more generalisable.

4. 4

   Why is a larger sample usually better than a small one?

   Model answer

   A larger sample is more likely to represent the target population. One unusual participant has less effect on the overall results.

5. 5

   Why can a researcher draw conclusions about a whole population from a sample?

   Model answer

   Scientific sampling assumes that a large, representative sample reflects the population it came from. Conclusions from the sample can then be generalised to that population.

6. 6

   How is a random sample selected?

   Model answer

   A random sample gives every member of the target population an equal chance of being chosen. Names can be drawn from a hat or picked by a computer.

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