Sampling

Question 1

What is random sampling?

Answer 1

Every member of target audience has equal chance of being selected
e.g. names out of a hat/computer generated

Question 2

Evaluate random sampling

Answer 2

Strength - no researcher bias
e.g. - Sample randomly generated, so researcher doesn’t have input
Ex. - Reduces possibility of biased sample serving their aims. Sample also representative of general population

Limitation - time consuming
e.g. - ensuring everyone in target population has equal chance
Ex. People in sample may not want to parti, meaning sample more akin to volunteer

Question 3

What is systematic sampling?

Answer 3

Predetermined system used to select parties
e.g. every 5th person

Question 4

Evaluate systematic sampling

Answer 4

Strength - no researcher bias
e.g. - researcher has no input, following predetermined system
Ex. - Reduces potential influence investigator may have obtaining sample

Limitation - Not truly unbiased
e.g. - Every Nth person could have characteristic in common (right-handed)
Ex. - Sample generated may not be representative - generalisation to general public more difficult

Question 5

What is stratified sampling?

Answer 5

Subgroups within population identified
participants obtained from each stratum in proportion to occurrence within population

e.g. if psychology class has 18 girls & 2 boys & researcher wants sample of 10 for study, sample would be 9 girls 1 boy

Question 6

Evaluate stratified sampling

Answer 6

Strength - no researcher bias
e.g. - Sample generated randomly once subcategories identified
Ex. - Reduces possibility of researcher choosing bias sample - sample representative as each subgroup represented in sample.
This means findings can be generalised to target population with greater confidence

Limitation - difficult & time consuming
e,g, - ensuring subgroups in target population all accurately identified
stratification imperfect - subgroups identified can’t reflect all individual differences that exist between those in target population
Ex. - Truly representative sample would be extremely difficult to obtain using this technique

Question 7

What is opportunity sampling?

Answer 7

Selected anyone who’s available & willing to take part in study at same time - technique often used in psychological research due to ease of application
E.g. gathering opportunity sample from school of 500 A-Level students would involve approaching students in sixth form centre during free period to ask them to participate in study, first 20 to agree would be used

Question 8

Evaluate opportunity sampling

Answer 8

Strength - convenient
E.g. obtaining opportunity sample quicker & easier than other sampling methods as requires less effort on behalf of researcher
Ex. - saves money & favoured as economical technique

Limitation - bias
E.g. - if looking in sixth form centre, only students available to take part - not representative of target population. Also incensed risk of investigator bias as researcher has complete control over who they approach
Ex. - may select particular individuals & avoid others according to own subjective preferences

Question 9

What is volunteer sampling?

Answer 9

Participants self-selecting to take part in study by either volunteering when asked or by responding to advert
E.g. psychologist puts posters in various locations around school looking for A-Level students to volunteer to take part in study, providing e-mail address to reply to or time/date/venue to attend. First 20 volunteers form sample

Question 10

Evaluate volunteer sampling

Answer 10

Strength - quicker & easy
E.g. - parties approach research rather than other way round - technique requires minimal effort & input from researcher
Ex. - process quicker & easier than other sampling

Limitation - bias
E.g. - particular type of person takes part in research & only those who see poster will attend
Ex. - Sample likely to be biased & not representative of target population - makes generalisation of findings more difficult