RM: Sampling Methods

Question 1

What is the target population?

Answer 1

-the group of people the researcher wants to study

Question 2

Why is the target population used?

Answer 2

-not everyone can be studied, so samples are collected

Question 3

What is the critical feature of the sample?

Answer 3

-the sample must be representative of the target population

Question 4

What is the key limitation of the sample?

Answer 4

-the findings of the study can only be applied to the target population that the sample is representative of

Question 5

What does sampling enable us to do?

Answer 5

-if the sample is representative, you can generalize the results to the wider population

Question 6

What is random sampling?

Answer 6

-each member of the target pop. have an equal chance of being chosen
-all names are entered into an online database and a random system picks the sample

Question 7

What is a sampling frame?

Answer 7

-a complete list of all the members of the target population

Question 8

How are ppts selected from a sampling frame?

Answer 8

-all the names on a list are assigned a number, and the sample is selected randomly (computer-based randomizer)

Question 9

Advantages of random sampling?

Answer 9

-no researcher bias (everyone has equal chance of being chosen)
-more likely representative

Question 10

Disadvantages of random sampling?

Answer 10

-impractical- more time/effort than other methods (list of target pop. needed, then identify sample)
-not completely representative- unbiased selection does not mean unbiased sample

Question 11

What is opportunity sampling and how is it conducted?

Answer 11

-recruiting anyone who is available at the time of the study
-researcher asks any members of the target population to take part in the research
-the researcher could bias the sample (lacks internal validity)

Question 12

Advantages of opportunity sampling?

Answer 12

-simple, quick, and easy- using first ppts you find
-useful for naturalistic experiments- researcher had no/little control over who is being studied

Question 13

Disadvantages of opportunity sampling?

Answer 13

-unrepresentative- sample is likely to be biased (excludes certain types of ppts)
-findings can’t be generalised

Question 14

What is volunteer sampling and how is it conducted?

Answer 14

-ppts offer to take part after finding out about the research
-self-selecting by responding to an advert

Question 15

Advantages of volunteer sampling?

Answer 15

-most convenient and economical method to gather a range of people with particular requirements
-can reach a wide audience, especially online

Question 16

Disadvantages of volunteer sampling?

Answer 16

-sampling bias- particular people are more likely to volunteer
-this may lead to a bias- similar characteristics in ppts
-harder to generalise

Question 17

What is systematic sampling and how is it conducted?

Answer 17

-ppts are selected from the sampling frame at regular intervals
-a sampling system is nominated (every 3rd/6th person)
-researcher works through frame until sample is complete

Question 18

Advantages of systematic sampling?

Answer 18

-simple to conduct
-eliminates researcher bias (objective system)

Question 19

Disadvantages of systematic sampling?

Answer 19

-not truly unbiased (not equal chance of being represented)
-requires a sampling frame

Question 20

What is stratified sampling and how is it conducted?

Answer 20

-characteristics of sample ppts are in same proportion as in target pop.
-identify how many are in each strata, then work out the % of each strata that makes up the target pop.

Question 21

Advantages of stratified sampling?

Answer 21

-most representative (equal representation of subgroups)
-generalisable

Question 22

Disadvantages of stratified sampling?

Answer 22

-knowledge of pop. characteristics required
-time consuming