Sampling Flashcards
what is volunteer/self-selecting sampling?
consists of ppts becoming part of a study because they volunteer when asked or respond to adverts
what are STRENGTHS of volunteer sampling?
- convenient
- no bias from experimenter in choice of ppts
- people given some form of consent by volunteering
what are WEAKNESSES of volunteer sampling?
-bias depending on where they put advertisement-might skew sample
what is random sampling?
sample in which every member of population have equal chance of being chosen
-involves identifying everyone in target population-en selecting number of ppts needed in a way that gives everyone in population equal chance-usually using number generator
what are STRENGTHS of random sampling?
-best chance of unbiased representation of target population-equal chance of being selected
what are WEAKNESSES of random sampling?
- difficult to do when target population is large
- still may not be completely representative
what is opportunity sampling?
consists of taking sample from people who are available at the time and fit criteria you are looking for
what are STRENGTHS of opportunity sampling?
-quick and convenient-everyone in one place
what are WEAKNESSES of opportunity sampling?
-unrepresentative of target population-all share characteristics
what is stratified sampling?
involves classifying population into categories-then choosing sample which consists of ppts from each category in same proportions as they are in population
what are STRENGTHS of stratified sampling?
-more representative of wider population-all categories of target population are represented
what are WEAKNESSES of stratified sampling?
- difficult and time-consuming-calculating number os people needed
- certain groups may be overlooked in sampling
