Sampling

Question 1

What is a sample?

Answer 1

The group od people who take part in research

Question 2

What is the population?

Answer 2

The population refers to the entire group of individuals who the researcher may be interested in studying

Question 3

What is the target population?

Answer 3

A sub-group of the population that the psychologist intends to conduct research and draw conclusions from

Question 4

What are the sampling techniques?

Answer 4

• Random sampling
• Opportunity sampling
• Volunteer sampling
• Systematic sampling
• Stratified sampling

Question 5

What is random sampling?

Answer 5

All participants from the target population have an equal chance of being selected. They are selected without bias, from ‘out of a hat’

Question 6

What is a strength of random sampling?

Answer 6

It is unbiased
- It is free from researcher bias. The researcher has no influence over who is selected and this prevents them from choosing people who think may support their hypothesis

Question 7

What are 3 limitations of random sampling?

Answer 7

Time consuming
- A complete list of the target population may be extremely difficult to obtain
May still not be representative
- The laws of probability suggest that random sampling is likely to produce a more representative sample than, for example, opportunity sampling. However, it is still possible that the random method may select, for example, 20 female psychology teachers from Lancashire called Barbara.
Refusing to take part
- Selected participants may refuse to take part (which means you end up with something like a volunteer sample)

Question 8

What is opportunity sampling?

Answer 8

Selecting people who are willing to take part

Question 9

What is a strength of opportunity sampling?

Answer 9

Quick, easy and convenient
- This method saves a researcher a good deal of time and effort and is much less costly in terms of money than, for example, random sampling

Question 10

What are 2 limitations of opportunity sampling?

Answer 10

Unrepresentative
- It is drawn from a specific area, such as one street in one town, so findings cannot be generalised to the target population
Researcher bias
- The researcher has complete control over the selection of participants and, for instance, may avoid people they do not like the look of

Question 11

What is volunteer sampling?

Answer 11

Participants put themselves forward for the research, usually through responding to an advert

Question 12

What is a strength of volunteer sampling?

Answer 12

Convenient
- Collecting a volunteer sample is easy. It requires minimal input from the researcher and so is less time-consuming than other forms of sampling.

Question 13

What is a limitation of volunteer sampling?

Answer 13

Volunteer bias
- Asking for volunteers may attract a certain ‘profile’ of person, that is, one who is helpful, keen and curious, which might affect how far findings can be generalised

Question 14

What is systematic sampling?

Answer 14

The target population is arranged in some sort of order, then every ‘nth’ person is selected

Question 15

What is a strength of systematic sampling?

Answer 15

Avoids researcher bias
- Once the system for selection has been established the researcher has no influence over who is chosen

Question 16

What is a limitation of systematic sampling?

Answer 16

Can be unrepresentative and time consuming
- It is still possible for a similar group of people to be chosen using this method, although it would be unlikely

Question 17

What is stratified sampling?

Answer 17

The researcher identifies the different type of people that make up the target population and works out the proportion of the population each sub-group represents. Each sub-group needs to then be proportionally represented in the sample.

Question 18

What are 2 strengths of stratified sampling?

Answer 18

Avoids researcher bias
- Once the target population has been sub-divided into strata, the participants that make up the numbers are randomly selected and beyond the influence of the researcher
Representative
- This method produces a representative sample because it is designed to accurately reflect the composition of the population. This means that generalisation of findings becomes possible

Question 19

What is a limitation of stratified sampling?

Answer 19

Time consuming and not perfect
- This method is time consuming and also cannot reflect all the ways that people are different, so complete representation of the target population is not possible