Sampling

Question 1

define ‘population’?

Answer 1

-large group of people who are the focus of researchers interest

Question 2

explain a ‘random sample’?

Answer 2

• a form of sampling so all members of target population have a chance to be selected
• complete list of all members of target population obtained
• all names given a number
• samples generated through lottery method/randomiser

Question 3

evaluate a ‘random sample’

Answer 3

+free from researcher bias, as researcher cannot control who is selected

• time consuming
• may end up with an unrepresentative sample
• selected pp’s may refuse to take part

Question 4

explain a systematic sample?

Answer 4

• when every nth member of a target population is selected
• sampling frame produced with target population organised into a specific order
• the system is then chosen eg. every 6th person

Question 5

evaluate a systematic sample?

Answer 5

• avoids researcher bias, once system selection is allocated researcher cannot influence who is chosen
• fairly representative, but can sometimes produce an unrepresentative sample

Question 6

explain a stratified sample?

Answer 6

• reflects proportions of people in certain subgroups(strata) within target population
• researcher identifies different strata that makes up population
• proportions needed for sample to be representative are worked out
• pp’s that make up each strata are selected using random sampling

Question 7

evaluate a stratified sample?

Answer 7

+avoids researcher bias as pp’s once subdivided are randomly selected
+produces a representative sample
+generalisation is possible
-cannot reflect all the ways people are different, so complete representation is not possible

Question 8

explain an opportunity sample?

Answer 8

• researchers select anyone willing or available

- may ask whoever is around at the time of the study.

Question 9

evaluate an opportunity sample?

Answer 9

+convenient, saves time, effort and money.

• sample is unrepresentative of target population as may be drawn from one specific area
• researcher has control over selection= researcher bias

Question 10

explain a volunteer sample?

Answer 10

• pp’s selecting themselves= self selection

- eg. seeing advertisement in newspaper

Question 11

evaluate a volunteer sample?

Answer 11

+saves time with minimal input from the researcher

-volunteer bias as advert may attract a certain ‘profile’ of person, affecting how findings can be generalised