Sampling

Question 1

What does ‘sampling’ refer to?

Answer 1

Groups of people (participants) that form part of research studies are selected through the process of ‘sampling’

Question 2

How many important sampling techniques are used?

Answer 2

5

Question 3

Name the 5 different sampling techniques

Answer 3

Random sample, systematic sampling, stratified sample, opportunity sampling and volunteer sample

Question 4

What does target population refer to when regarding sampling?

Answer 4

Population refers to the large group of individuals that the researcher is interested in studying. This is often called the target population because its group of the general population

Question 5

Why do researchers use samples?

Answer 5

For practical and economical reasons the researcher cannot include all the target population into their research so instead they select a smaller group, known as a sample
The sample should be representative of the target population so that generalisation of findings can occur

Question 6

Describe random sampling

Answer 6

All members of the target group have an equal chance of being selected
A complete list of all members of the target population are obtained and all the members are allocated a number
The sample is selected through the use of a lottery method - computer generated, randomiser, picking numbers from a hat

Question 7

What are some advantages of random sampling?

Answer 7

1. Random sample is potentially unbiased
2. EV’s should be equally divided between the different groups which enhances internal validity

Question 8

What are some disadvantages of random sampling?

Answer 8

1. It is difficult and time-consuming to conduct - getting a list of the target population may be difficult to obtain
2. You may end up with a sample that is unrepresentative
3. Selected participants may refuse to take part

Question 9

What is systematic sampling?

Answer 9

This is when every nth member of the target population is selected
EG: every 3rd house on the street, every 5th pupil on the school register or every 3rd sweet when lined up

How it takes place:
A sampling frame is produced - a list of people in the target population organised (eg. in alphabetical order)
A sampling system is nominated (eg. every 3rd, 6th or 8th person)
The researcher then works through the sampling frame until the sample is complete

Question 10

What is an advantage of systematic sampling?

Answer 10

1. Free from researcher bias

Question 11

What are some disadvantages of systematic sampling?

Answer 11

1. It may not be truly unbiased - its possible that the sample may have similar traits
2. The sample generated may not be representative, making generalisation on the target population more difficult
3. Time-consuming and the participants may refuse to take part

Question 12

What is stratified sampling?

Answer 12

Subgroups (strata) within a population are identified
First the researcher needs to identify the different strata that make up the population
Then the proportions needed for the sample to be representative are worked out
Finally the participants that make up each stratum are selected using random sampling

Question 13

What are some advantages of stratified sampling?

Answer 13

1. Produces a representative sample as its designed to accurately reflect the composition of the population
2. Generalisation of the findings become possible
3. Free from researcher biased

Question 14

What are some disadvantages of stratified sampling?

Answer 14

1. They can be difficult to do and time-consuming
2. The identified strata cannot reflect all the ways that people are different
3. Complete representation of the target population is not possible

Question 15

What is opportunity sampling?

Answer 15

Consists of selecting anyone who is available and willing to take part in the study at the time
The researcher takes the chance to ask whoever is around at the time of their study

Question 16

Give an advantage of opportunity sampling

Answer 16

1. This method is convenient - quicker and less costly as specific target populations are not required

Question 17

Give some disadvantages of opportunity sampling

Answer 17

1. Not representative of the target population as its drawn from a very specific area or location so findings can’t be generalised to the target population
2. The researcher has control over the selection and therefore there may be researcher bias

Question 18

What is volunteer sampling?

Answer 18

This involves participants selecting themselves to be part of the sample
It is also called self-selection

Ways in which a volunteer sample may be gathered:
Place advert on social media/ newspaper/ common room at University
Asking people to raise their hand when the researcher requests participants

Question 19

Give some advantages of volunteer sampling

Answer 19

1. An easy and cheap method
2. Requires minimal input from the researcher
3. The participants should be more engaged/ enthusiastic

Question 20

Give some disadvantages of volunteer sampling

Answer 20

1. Volunteer bias is a problem
2. Very often it’s a specific type of person who is more likely to volunteer to take part in research
3. They may be more curious and more likely to please the researcher