Sampling

Question 1

Population

Answer 1

A group of people who are the focus of the researchers interest, from which smaller sample is drawn.

Question 2

Sample

Answer 2

A group of people who take part in a research investigation. Sample is drawn from target population and presumed to be representative of that population.

Question 3

Random sample

Answer 3

All members of target population have equal chance of being chosen. Get a list of all people in the target population, give each a number, use a lottery method to select px’s.

Question 4

Random sample evaluation

Answer 4

Strengths
Potentially unbiased way of selecting px’s.

Limitations
Time consuming. May still end up with an unrepresentative sample (lottery method could select all males).

Question 5

Systematic sample

Answer 5

Every nth member of the target population is selected. Sampling frame is produced (list of people in the target population organised into i.e. alphabetical order). sampling system nominated (i.e. every 3rd person).

Question 6

Systematic sample evaluation

Answer 6

Strengths
Method is objective- researcher has no influence on who is chosen.

Limitations
Time consuming. Px’s chosen may refuse to participate in the study so ends up being more like a volunteer sample.

Question 7

Stratified sample

Answer 7

Composition of sample reflects proportions of people in certain subgroups within the target or wider population.

Question 8

Stratified sample evaluation

Answer 8

Strengths
Representative sample as accurately reflects composition of population. Generalisation of the findings is possible.

Limitations
Complete representation isn’t possible.

Question 9

Opportunity sample

Answer 9

Ask whoever is around at the time of the study.

Question 10

Volunteer sample

Answer 10

Px’s select themselves to be part of the sample. May be advert in newspaper, noticeboard in common room, px raise hand when asked by researcher.

Question 10

Opportunity sample evaluation

Answer 10

Strengths
Convenient, less costly in terms of money and time.

Limitations
Suffers from bias. Sample is unrepresentative as all from one specific area so we cannot generalise. Researcher bias is possible as they may avoid some people they don’t like the look of.

Question 10

Volunteer sample evaluation

Answer 10

Strengths
Easy- minimal input from researcher. The participants will be engaged with the study.

Limitations
Volunteer bias is problem- may attract a certain ‘profile’ of person e.g. curious, likely to try and please the researcher.