Sampling

Question 1

‘Sample’ definition

Answer 1

A small representative group drawn from the survey population for questioning or interviewing

Question 2

‘Sampling method’ definition

Answer 2

The techniques used to select representative individuals to tudy for a survey population

Question 3

‘Sampling frame’ definition

Answer 3

A list of people in a population used as the source for a sample - names, postcodes, NI numbers, etc.

Question 4

Simple random sampling definition and strengths/weaknesses

Answer 4

Based on the probability that the random selection of names from a sampling frame will produce a sample that is representative of a target population.

+ For very large samples it provides the best chance of an unbiased representative sample - every member has an equal chance

• For large populations it is time consuming to create a list of every individuals. It’s very difficult to be truely random, it may not give equal proportion, e.g, 20 blondes 2 brunettes.

Question 5

Systematic sampling definition and strengths/weaknesses

Answer 5

Every nth person in sampling frame is selected.

+ unbiased samples from large populations
+ generally representative, due to the list containing every member of the target population

• In some situations using a system to select participants can make the sample biased, e.g, by picking every 10th house you might only pick out ‘corner houses’ etc

Question 6

Stratified sampling definition and strengths/weaknesses

Answer 6

In attempt to remove errors creted by simple random sampling, a popuation is subdivided according to known criteria. Gender, age, class, ethnicity, education. A random sample is then selected from each list.

+ the deliberate effort to make the sample reoresentative of the target population

• it can be time consuming as the subcatagories have to be identified annd proportions calculated.
• samples are often influenced by the researcher in order to get equal representation of a group, which may not reflect the wider population

Question 7

Snowball sampling definition and strengths/weaknesses

Answer 7

Involves the researcher identifying someone in the target population who is willing to e researched. This person may then suggest another 2 or 3 people who will help. The rsearcher snowballs of participants.

+ a useful way of finding participants with a certain attribute who might not wish be found otherwise
+ consent is usually assumed by volunteer participants