Sampling

generalisation definition

if findings can be broadly applied to the population

explain random sample

where all members of target population have and equal chance of being selected- they are picked using a randomizer to reduce bias

explain systematic sample

is where every nth member of the population is selected- for example every 3rd person

explain stratified sample

researcher divides a whole population into smaller groups called strata based on shared characteristics

explain opportunity sample

if target population is difficult to obtain- researchers choose to select anyone nearby or available

explain volunteer sample

involves participants selecting themselves to be a part of the sample- volunteering

disadvantages of random sampling

-difficult and time consuming to conduct- complete list of target population is hard to obtain

-may still be left with a sample that is unrepresentative

disadvantages of systematic sampling

-time consuming

-participants might choose to withdraw and result in biased sample

disadvantages of stratified sample

-identified strata cannot reflect all the different subgroups- complete representation of target population is not possible

disadvantages of opportunity samples

-biased because participants in a certain area probably have a specific demographic so cannot be generalised to target population

disadvantages of volunteer sample

volunteer bias- asking for volunteers might attract a certain type of person- usually curious and more likely to try and please researcher