Research Methods Y1 Flashcards
What is the definition of a population?
A group of people who are the focus of the researchers interest, from which a smaller sample is drawn.
What is the definition of a sample?
A group of people who take part in a research investigation.
Where is a sample drawn from?
From a target population and is presumed to be representative of that population.
What is the definition of bias?
When certain groups are over- or under-represented within the sample selected.
What is the negative effect of bias?
It limits the extent to which generalisations can be made to the target population.
What is the definition of generalisation?
The extent to which findings and conclusions from a particular investigation can be broadly applied to the population.
When is generalisation possible?
If the sample of participants is representative of the population.
Why is it often called a ‘target population’?
It is a subset of the general population.
Why are samples used?
For practical and economic reasons, it is usually not possible to include all members of a target population -> researcher uses a smaller group.
What should samples ideally be and why?
Representative of the target population so that generalisation of findings become possible.
Why is it often very difficult to represent populations?
Due to the inevitably diverse nature of populations, e.g, different age, ethnicity, gender.
What are the 5 main sampling techniques?
Random sampling, Systematic sampling, Stratified sampling, Opportunity sampling, Volunteer sampling.
Why are sampling techniques used?
In attempt to produce a representative sample.
What is a random sample?
A form of sampling in which all members of the target population have an equal chance of being selected.
What are the steps of random sampling?
1- Obtain a complete list of all members of the target population.
2- All the names of the list are assigned a number.
3- The actual sample is selected through the use of some lottery method - a computer/phone randomiser or picking numbers from a hat.
What is a systematic sample?
When every nth member of the target population is selected.
What is produced in systematic sampling and what is it?
A sampling frame - a list of people in the target population that are organised some way.
What happens after a sampling frame is produced in systematic sampling?
A sampling system is nominated (e.g, every 3rd person) and the researcher then works through the sampling frame until the sample is complete.
What is a stratified sample?
A form of sampling in which the composition of the sample reflects the proportions of people in certain subgroups within the target population/wider population.
What are the steps of stratified sampling?
1- The researcher identifies the different strata that make up the population.
2- The proportions needed for the sample to be representative are worked out.
3- The participants that make up each stratum are selected using random sampling (hat/random number generator).
What is an opportunity sample?
Where the researcher simply takes the chance to ask whoever is around at the time of their study to participate, e.g, in the street.
What is a volunteer sample?
Involves participants selecting themselves to be part of the sample.
How would a volunteer sample potentially be selected?
A researcher may place an advert in a newspaper or on a common room noticeboard.
Strength of a random sample and why?
Potentially unbiased - means that confounding variables or extraneous variables should be equally divided between the different groups - enhancing internal validity.