Sampling

Question 1

Target Population

Answer 1

The particular group of people that you are interested in studying.

Question 2

Sample

Answer 2

The participants in a research study. The sample needs to be selected from the target population.

Question 3

Sample Size

Answer 3

Number of participants taking part in a study.

Question 4

Why is Sampling important?

Answer 4

It is important that the sample is representative of the target population so the findings can be generalised back to the target population. If the sample is not representative of the target population the sample is said to be biased. Sampling is a consideration when judging the population validity of research.

Question 5

What is External Validity?

Answer 5

The extent to which findings can be generalised to settings other than the research settings. This includes population validity, which refers to whether the results can be generalised to other people in the target population other than the research participants. The population validity of the research in psychology has been questioned (sample size, American dominance, Western cultures).

Question 6

What are the 3 types of sampling?

Answer 6

1. Random sampling
2. Opportunity sampling
3. Volunteer sampling

Question 7

Sampling

Answer 7

One of the first steps in a social research is to decide on the group of people to be studied. This group is called the target population. The choice of target population will depend on the hypothesis. For example, a hypothesis like ‘teachers treat males more favourable than females’ might mean that the target population would include all pupils and teachers in a particular school.

Question 8

Sample

Answer 8

A sample is simply a small group drawn from the target population. It is a way of making general statements about the whole target population based on the responses of a small percentage of the whole target population. If the results obtained are to be generalised (applied to the rest of the population), it is important that the sample is representative (individuals are typical of a wider target group). Psychologists obtain representative samples by using various sample methods.

Question 9

Sampling Frame

Answer 9

A sampling frame is a list of all those included in the target population from which the sample will eventually be selected. For example, the names of all school children in a school taken from the registers.

Question 10

Sampling Method

Answer 10

A sampling method is the process by which the psychologist selects representative individuals from the sampling frame.

Question 11

Sample Size

Answer 11

The size of the sample will depend on the time and money available. However, if the sample is too small the findings may not be representative of the whole target population.

Question 12

Random methods

Answer 12

• Contains a sampling frame (list of names)
• Large sample

Question 13

Name some random methods of sampling

Answer 13

1. Simple random sampling
2. Stratified random
3. System sampling

Question 14

Simple random sampling

Answer 14

Each individual in the survey population has an equal chance of selection, and names are selected from the sampling frame at random.

Question 15

Stratified random

Answer 15

The sampling frame is divided into strata (sub-groups) and a random sample is chosen from each stratum.

Question 16

Systematic sampling

Answer 16

A series of names is taken at regular intervals from the sampling frame.

Question 17

Non-random methods

Answer 17

• No sampling frame
• Smaller sample

Question 18

Name some non-random methods of sampling

Answer 18

1. Quota sampling (opportunity)
2. Snowball sampling (volunteer)

Question 19

Quota sampling (opportunity)

Answer 19

People of different types are chosen by interviewers to ensure a certain number of each type in the sample.

Question 20

Snowball sampling (volunteer)

Answer 20

Start with one member of the population and that person will divulge the name of others who might cooperate.