sampling technique's Flashcards
what is meant by a population ?
the group of people from whom the sample is drawn
what is meant by a sample ?
a small group chosen to represent the population
why do psychologists use sampling technique’s ?
- it is not usually possible to test everyone in the population
what sampling methods are there ?
- random sample
- opportunity sample
- volunteer (self elected) sample
- systematic sampling
- stratified sampling
random sample
all members of the population have an equal chance of being selected
strengths and limitations of random sample ?
strengths
- potentially unbiased
- likely to produce a more representative sample of results
limitations
- difficult + time consuming
opportunity sample
- selecting anyone who is willing and available
strengths of opportunity sample
- convenient
- less costly
- list of members not required
- no need to divide population
limitations of opportunity sample
- sample is unrepresentative of target population so findings cannot be generalised
- researcher bias
volunteer sample
involves ps selecting themselves to be part of a sample (self selection)
strengths of volunteer sample
- minimal input
- less time consuming
- ps are more engaged
limitations of volunteer sample
- volunteer bias
- they are more likely to try and please researcher
systematic sampling
- when every nth member of the target population is selected
strength of systematic sampling
- objectivity
limitations of systematic sampling
- time consuming
- ps may refuse take part resulting in volunteer bias
