Paper 2 - Research methods - Sampling methods

Question 1

Define target population

Answer 1

The specific group of people from the whole population you want to study

Question 2

Define sample

Answer 2

The smaller group of people you select from the target population to participate in the study

Question 3

What are the types of sampling methods

Answer 3

-Volunteer
-Systematic
-Opportunity
-Stratified
-Random

Question 4

Outline volunteer sampling

Answer 4

Where participants put themselves forward to be included (Self-select) to take part. They are not directly asked to take part (E.g an advert is posted)

Question 5

Outline systematic sampling

Answer 5

A sampling frame is produced of the potential participants and organised. A sampling pattern is then chosen (E.g every nth person)

Question 6

Outline opportunity/convenience sampling

Answer 6

The researcher directly asks the participants who are readily available to participate

(E.g a university lecturer asks students to participate)

Question 7

Outline stratified sampling

Answer 7

The composition of the sample reflects the proportions of subgroups (Known as strata) in the target population. Strata are identified then the percentage proportion of each are calculated. Random sampling of each strata is then done until the correct proportions are matched

Question 8

Outline random sampling

Answer 8

The researcher first obtains a list of potential participants. They are then chosen by chance to take part until the required number for the sample is achieved

Question 9

Define bias

Answer 9

When the validity of research findings may be affected by a researchers influence over data collection, analysis or interpretation

Question 10

Which sampling methods are more prone to bias and why?

Answer 10

-Opportunity - Investigator bias is likely as the investigator directly asks participants to take part

-Volunteer - People who volunteer themselves have shared characteristic in motivation to participate

-Stratified - The investigator picks the individual strata

Question 11

Which sampling methods are less prone to bias and why?

Answer 11

-Random - Researcher has no say in who is picked

-Systematic - Participants are chosen by chance

-Stratified - Random sampling of strata

Question 12

Define generalisability

Answer 12

The extent to which the findings from a study on a particular sample can be applied to a broader target population

Question 13

Which sampling methods are more generalisable and why?

Answer 13

-Stratified - Reflects the percentage proportion of stratas of target population

-Random + systematic - Have the capacity to be representative

Question 14

Which sampling methods are less generalisable and why?

Answer 14

-Volunteer - Shared characteristics around participants

-Opportunity - Researcher directly asks people to be part of the study

-Random + Systematic - Due to it being by chance it may not be fully representative

Question 15

Why is bias important?

Answer 15

As it is important we gather valid results

Question 16

Why is generalisation important

Answer 16

To gather an understanding of human behaviour so it be representative of a large population

Question 17

What are the benefits of random sampling?

Answer 17

-It is likely to be reliable
-As the researcher has no control over who is selected which therefore reduces the chances of bias in the sample being selected
-Therefore potentially controlling for participant variables and increasing validity

Question 18

What are the drawbacks of random sampling?

Answer 18

It does not guarantee a representative sample
-As the method of choosing participants is due to chance so some participant variables may not be represented at all
-Therefore it could be unrepresentative making generalisability difficult

-Can be time consuming too and may not be time efficient if there is a large sample
-Due to the fact the sampling frame needs to be known and everyone needs to be allocated a number for selection

Question 19

What are the benefits of opportunity sampling?

Answer 19

-The participant sample is easy to obtain and therefore more cost effective
-The researcher asks people and chooses them to volunteer
-Therefore a sampling frame does not need to be identified prior to the research taking place making it quicker and easier to conduct

Question 20

What are the drawbacks of opportunity sampling?

Answer 20

-Sample is likely to be unrepresentative
-The researcher uses their own choices to directly ask the participants
-Therefore participants are more likely to share similar characteristics and backgrounds reducing population validity and making it harder to generalise findings

-There is potential for investigator bias
-As the researcher selects participants who are close and readily available to take part, which means they could select participants to fir there standards
-Reducing validity of the findings

-Potential for ethical reasons
-People may feel pressured or obliged to take part

Question 21

What are the benefits of volunteer sampling?

Answer 21

-May be the only way to locate a particularly niche group of people
-The researcher can advertise for this specific group who may be otherwise difficult to identify
-This can therefore allow topics to be studied that otherwise may not be possible

Question 22

What are the drawbacks of volunteer sampling?

Answer 22

-The sample gained may lack generalisability and may not be representative
-The researcher uses posters/adverts to gather people’s interest
-So participants will be motivated
-Therefore this limits participant variables as it fails to reflect a wide variety of the population

Question 23

What are the benefits of systematic sampling?

Answer 23

-Avoids researcher bias
-Once the system for selection has been establish, the researcher has no influence over who is chosen
-This increases the validity and leads to a more representative sample so findings are more generalisable

Question 24

What are the drawbacks of systematic sampling?

Answer 24

-The sampling method does not guarantee a representative sample
-Even though in theory the participants chosen should be by chance some groups may be overrepresented or not selected by chance
-So it may be less representative than other methods like stratified

Question 25

What are the benefits of stratified sampling?

Answer 25

-**Avoids researcher bias** -Once subdivided into their strata, the sampling method ensures that all groups from the target population are **represented** and the researcher has **no influence** over who is chosen -This gives an **accurate reflection of the target population** which gives high generalisability

Question 26

What are the drawbacks of stratified sampling?

Answer 26

-It is **more time consuming** compared to other methods -As the sample need to be broken into strata which a percentage proportion is then calculated -Which takes time -It isn't completely comprehensive -Identified strata cannot reflect all possible sub-groups -Therefore **complete representation of target population is not always possible**