sampling

Question 1

what is the target population

Answer 1

the population refers to the large group of individuals that a particular researcher may be interested in studying

e.g. students attending colleges in the North West

Question 2

why can’t we include all members of the target population

Answer 2

• for practical and economical reasons

Question 3

what is the sample

Answer 3

as the researcher can’t study all the members of target population, they select a smaller group.

This group is known as the sample

Ideally, the sample that is drawn should be representative of their target population so that generalisation of findings becomes possible

Question 4

why is it difficult to represent the whole population in a sample

Answer 4

it is often difficult to represent a whole target population in a given sample due to their diverse nature

Therefore, a vast number of samples contain bias

Question 5

what are the different sampling techniques that are used to create a sample

Answer 5

1. random sampling
2. systematic sampling
3. stratified sampling
4. volunteer sampling

Question 6

what is random sampling

Answer 6

in random sampling all members of the target population have an equal chance of being selected

HOW DOES THIS WORK:

1. firstly, a complete list of all members of the target population is obtained
2. all of the names on the list are assigned a number
3. the sample is generated through the use of some lottery method ( a computer - based randomiser or picking numbers from a hat)

Question 7

what is a systematic sample

Answer 7

a systematic sample is when every nth member of the target population is selected

e.g. every 3rd house on a street

HOW DOES THIS WORK:

• a sampling frame is produced, which is a list of people in the target population organised into e.g. alphabetical order
• a sampling system is then nominated ( every 6th, 3rd, or 8th person e.t.c) or this interval may be determined randomly to reduce bias
• the researcher then works through the sampling frame until the sample is complete

Question 8

what is stratified sampling

Answer 8

stratified sampling is a sophisticated form of sampling

the composition of the sample reflects the proportions of people in certain sub - groups ( strata) within the target population

HOW DOES THIS WORK:

• researcher first identifies the different strata that make up the population. The proportions needed for the sample to be representative are worked out
• the participants that make up each stratum are selected using random sampling

Question 9

what is opportunity sampling

Answer 9

representative samples of target populations are so difficult to obtain, many researchers simply decide to select anyone who happens to be willing and available
(opportunity sample)

HOW DOES THIS WORK:
thee researcher simply takes the chance to ask whoever is around at the time of their study, e.g. in the street

Question 10

what is volunteer sampling

Answer 10

in volunteer sampling, participants selecting themselves to be part of the sample

HOW DOES THIS WORK:

the researcher may place an advert in a newspaper or on a room in a notice board