9.1.2 - Sampling techniques Flashcards
What are the 4 types of sampling?
Random
Stratified
Opportunity
Volunteer
Describe the technique of ‘random sampling’. (2 points)
Every member of the target population has a chance of being selected
Participants are randomly selected manually or by a computer
Describe the technique of ‘stratified sampling’. (2 points)
The population is sorted into subgroups (gender, age, ethnicity)
A proportionate number of each subgroup based on occurrence in the population is randomly selected
Describe the technique of ‘opportunity sampling’.
Selecting participants who are available and willing to partake in the research
Describe the technique of ‘volunteer sampling’.
Individuals who actively volunteer or self- select to participate in research by responding to an advertisement by the researcher
What is the 1 advantage and 2 disadvantages of random sampling?
Advantages:
Reduces selection bias - everyone has the opportunity to be selected
Disadvantages:
Doesn’t guarantee a representative sample - sub-groups may be accidentally excluded
Impractical with large populations
What are the 3 advantages of stratified sampling?
Population is more likely to be sampled evenly
Population is more likely to include sub-groups - increased generalisability
Limits the number of participants required to obtain a representative sample
What are the 2 disadvantages of stratified sampling?
Particular characteristics like personality traits may be missed
Time consuming and costly
What are the 2 advantages of ‘opportunity sampling’?
Quick and practical method
More ethical - only participants who are willing to participate accept
What are the 2 disadvantages of ‘opportunity sampling’?
Selection bias - sample is made of self-selected participants, making it unrepresentative
Experimenter bias - researcher chooses participants for the study and may choose people they already know
What are the 2 advantages of ‘volunteer sampling’?
Large population may respond to advert
More ethical - volunteers approach researcher because they are interested and willing to participate
What are the 2 disadvantages of ‘volunteer sampling’?
Social desirability bias - co-operative participants who volunteer show demand characteristics to ‘please or displease’ the researcher, making findings invalid
Hawthorne effect - people interested in the topic may show excessively positive responses, causing artificially high, invalid results
