Sampling

Question 1

A01 Define

Population

Answer 1

Group of people from where sample is drawn

Question 2

Define

Sample

Answer 2

Group of people who take part in research.
* Sample is drawn from (Target) Population & is representative of that population so that generalisation of findings become possible

Question 3

What is a target population

Answer 3

Subset of general population

Question 4

A01

What is random sampling

Answer 4

• Each member of target population has equal chance of being in sample
  How to conduct:
• Each member of target population assigned number
• Random number generator/lottery method used to randomly choose participant

Question 5

A03

What is a strength of Random sampling

Answer 5

No researcher bias-researcher has no influence of who is picked
means extraneous & cofounding variabales equally divied between groups-enhancing internal validity

Question 6

What is a limitation of Random sampling

Answer 6

Time consuming & difficlut to get list of members of target population
*by chance participants could produce unrepresentative sample e.g too fewer memebers of one gender

Question 7

What is systematic sampling

Answer 7

Participants are chosen from a list of the target population
Every nth participant is chosen to form the sample
(e.g every 5th,10th or 100th name)
Process continues until sample required

Question 8

What is a strength of systematic sampling

Answer 8

• Avoids researcher bias as researcher cannot choose participants they want in sample-fairly representative
• If there is existing list of target population

Question 9

What is a limitation of systematic sampling

Answer 9

• Not truly unbiased

Question 10

What is a opportunity sample

Answer 10

Researchers directly asks available memeber of traget population
How to conduct:
1. Researchers directly asks memeber from target population to take part in research

Question 11

What is a strength of opportunity sample

Answer 11

Easy method of recruitment-reducing time it takes to conduct research & reducing cost involved

Question 12

What is a limitation of Opportunity sample

Answer 12

• Not representative of target population
  as its drawn from specific area
• Researcher bias-as can control who they want to select

Suffers from 2 forms o f bias

Question 13

What is a Volunteer sample

Answer 13

involves self selection-Participants select themselves to be part of sample

How to condcut:
Advertisement are placed -advert in newspaper or online

Question 14

What is a strength of Volunteer sample

Answer 14

Quick access to willing participants reducing time & cost
*

Question 15

What is a limitation of Volunteer sample

Answer 15

Sample not generalisable to target population- volunteer bias
those who take part likely have diff characteristics to target population-affects generalisability

Question 16

What is stratfied sampling

Answer 16

By selecting from within strata, Characteristics of participants within the sample are in the same proportion as found within target population
How to conduct:
1. Strata/subgroups identified along with the proportion of target population E.g gender, ethnicity
2. Random sampling used to select number of participants required from within each stratum

Question 17

What is a strength of Stratified sampling

Answer 17

Sample is representative of larger target population
means results found in the sample should be generalised to target population
As participants randomly chosen from within each stratum this avoids researcher bias

Question 18

What is a limitation of stratified sampling

Answer 18

Time consuming to establish strata & randomly select from each stratum