Sampling

Question 1

Target Population

Answer 1

The set of people researchers want to find out about.

Question 2

Sample

Answer 2

A small set of people taken from the target population.

Question 3

Sample Frame

Answer 3

The source material from which a sample is drawn.

Question 4

Representative

Answer 4

How well a sample reflects the target population.

Question 5

Opportunity Sample

Answer 5

Researcher uses people who are available at that time because it is easy and convenient.

Question 6

Opportunity Sample (Advantages)

Answer 6

-Quick and cheap
-Good for characteristics that we can assume are the same for everyone
-Only sampling method for some research methods (covert field experiment).

Question 7

Opportunity Sample (Disadvantages)

Answer 7

-Sample bias (probably similar culture, researcher might choose helpful looking people)
-Can decline to take part, so turns into volunteer sampling.

Question 8

Self-Selected Sampling

Answer 8

Researcher uses people who take part in a study because they volunteer when asked or have responded to an advert.

Question 9

Self-Selected Sampling (Advantages)

Answer 9

-Quick and Practical
-Can reach wider variety of participant.
-Ethical, participants consent to taking part.

Question 10

Self-Selected Sampling (Disadvantages)

Answer 10

-Sample bias (biased towards the type of person who volunteers for research).

Question 11

Random Sampling

Answer 11

Every member of the target population has to be available to the researcher.
Each person has an equal chance of being picked.

Question 12

Random Sampling (Advantages)

Answer 12

-Provides unbiased sample, most likely to be most representative.

Question 13

Random Sampling (Disadvantages)

Answer 13

-Time Consuming and often impossible
-If you have to ask permission it becomes volunteer research.

Question 14

Systematic Sampling

Answer 14

A whole list of the target population is needed to select participants from.
Names are systematically taken from each register, e.g. every 10th name.

Question 15

Systematic Sampling (Advantages)

Answer 15

-Provides unbiased sample, participants selected using an objective system.

Question 16

Systematic Sampling (Disadvantages)

Answer 16

-Not truly random unless you select a number using a random method.

Question 17

Stratified Sampling

Answer 17

Selecting participants in proportion to their frequency in the target population. Subgroups in the target population are identified and participants are selected at random for the sample in the same proportions.

Question 18

Stratified Sampling (Advantages)

Answer 18

-Most representative of target population as all subgroups are represented so we can generalize the results.
-It produces more precise estimates for subgroups than simple random sampling.

Question 19

Stratified Sampling (Disadvantages)

Answer 19

-It can be difficult to access a list of the entire population and classify every member into a sub group.
-Very time consuming to identify and allocate to subgroups to make sure that the sampling frame is truly representative to the target population. ​

Question 20

Quota Sampling

Answer 20

The same process as stratified sampling (subgroups identified) BUT the researcher chooses (using opportunity sampling) who becomes part of the sample for each subgroup.

Question 21

Quota Sampling (Advantages)

Answer 21

-Most representative of target population as all subgroups are represented so we can generalize the results.

Question 22

Quota Sampling (Disadvantages)

Answer 22

-It may increase the risk of researcher bias, as the researcher might choose people who are easy to approach or co-operative.
-It does not allow random selection of participants, which may introduce bias or inaccuracy.
-Very time consuming to identify and allocate to subgroups to make sure that the sampling frame is truly representative to the target population. ​

Question 23

What is the difference between Stratified and Quota Sampling?

Answer 23

Stratified- Once the characteristics of the target population are identified each participant is chosen RANDOMLY.
Quota- Once the characteristics of the target population are identified each participant is chosen via OPPORTUNITY SAMPLING- so participants don’t have equal chance of participating.

Question 24

Snowball Sampling

Answer 24

Snowball sampling is a non-probability sampling method where new units are recruited by other units to form part of the sample. Snowball sampling can be a useful way to conduct research about people with specific traits who might otherwise be difficult to identify (e.g., people with a rare disease).

Question 25

Snowball Sampling (Advantages)

Answer 25

-Enables a researcher to locate groups of participants who are difficult to access.
-It saves time for the researcher, as the referrals come from reliable sources.

Question 26

Snowball Sampling (Disadvantages)

Answer 26

-Unlikely to be representative of the target population as friends of friends, so the target population has no equal chance of being selected.​
-Sampling bias is likely to occur.

Question 27

Observational Sampling/Time and Event Sampling

Answer 27

Event Sampling- Allows researchers to observe ongoing behaviors that vary over time in a naturally-occurring environment.​

Time Sampling- A method of collecting data or information in which research participants are observed for a specific amount of time and whether or not a particular behavior occurs​.

Question 28

Observational Sampling/Time and Event Sampling (Advantages )

Answer 28

Event- Useful for recording observations of infrequent behaviors.
Time- Useful for recording observations of frequent behaviors.

Question 29

Observational Sampling/Time and Event Sampling (Disadvantages)

Answer 29

-A problem with event sampling is that if too many observations happen at once it may be difficult to record everything. ​

-A problem with time sampling is that some behaviors may be missed and therefore the observation may not be representative.