Unit 2/Part 3: Experimental Studies Flashcards
What is convenience sampling? Provide an example.
Convenience sampling involves selecting participants who are readily available. There is no attempt to make the same representative of the population e.g. A teacher using their class to conduct an experiment, or students picking their friends to be participants in an experiment.
What is a strength and weakness of convenience sampling?
Strength: it’s quick and time efficient
Weakness: may not be representative of population and can be biased.
What is random sampling? Provide an example.
Random sampling is a procedure which ensures that every member of the population has an equal chance of being selected as a member of the sample e.g. Pulling names out of a hat
What is a strength and weakness of random sampling?
Strength: everyone is given an equal chance of being selected.
Weakness: may not be representative of the population.
What is stratified sampling? Provide an example.
Stratified sampling ensures that the sample is proportionately representative of the population, based on one or more participant characteristics. Groups in the sample occur in the same proportion as in the population. This involves dividing the population to be sampled into distinct groups based on a common trait that may affect the DV (e.g. Gender, age, religion). Accurate lists of all the people win each stratum are obtained and random samples of proportionate size are drawn from within each strata e.g. If women make up 55% of the population, then they must make up 55% of the sample.
What is a strength and weakness of stratified sampling?
Strength: accurately represents the population
Weakness: time consuming
What are the 3 main research design methods?
➰ independent groups
➰ repeated measures
➰ matched participant
Explain the independent groups design research method.
This method randomly allocates participants to a different group. Participants are in one group only (experimental or control group)
What is a strength and weakness of the independent group design research method?
Strength: straightforward to administer (time efficient) and no order effects to control.
Weakness: less control over participant related extraneous variables and a larger sample size is needed.
Explain the repeated measures research design method.
This method uses the same participants in the experimental and control conditions.
What is a strength and weakness of the repeated measures research design method?
Strength: participant characteristics balance out exactly (no participant related extraneous variables) and fewer participants required.
Weakness: order effect (first task performance may alter second task performance). This can be overcome using counterbalancing (half participants do control then experimental and vice versa)
What are the 3 main sampling techniques?
Convenience sampling, random sampling and stratified sampling.
