Research Methods - Sampling Flashcards
What is a population?
The large group of people the researcher is interested in studying. e.g. sixth form students in England
What is a sample?
It isn’t usually possible to include all members of the study, so a smaller group is selected - the sample.
What should be considered when making up samples?
A sample should be drawn so that it is representative of the population and generalisations can be made.
A sample should not be biased in that certain groups (e.g men, students, elderly, americans) are over or under-represented.
What is random sampling and how is it done?
Every person in the target audience is given an equal chance of being selected using the lottery method - all members of the target population are ‘put in a hat’ and randomly selected.
What is systematic sampling and how is it done?
Participants are selected using a set system e.g. list in alphabetical order and every nth person is selected from a list of the target population.
What is stratified sampling and how is it done?
Sample reflects proportions of people in certain subgroups (strata) within a population. Subgroups (strata) are identified e.g. gender or age groups. The relative percentages of the subgroups in the population are reflected in the sample.
What is opportunity sampling and how is it done?
People who are simply available e.g. nearby. This is done by asking people e.g. ask students in sixth form common room or people who walk past you in the shopping centre.
What is volunteer sampling and how is it done?
Participants are self-selecting. This is achieved through advertising e.g. ad in a newspaper or on social media or by asking people to put their hand up.
Evaluate random sampling.
Strength: potentially unbiased so CVs and EVs are controlled and internal validity is enhanced.
Limitation: time-consuming and may not work. Complete list of population is hard to get and some participants may refuse to take part.
Evaluate systematic sampling.
Strength: unbiased and objective method.
Limitations: time and effort…a complete list of the population is required and you may as well use random sampling.
Evaluate stratified sampling.
Strength: representative method so more generalisable compared to other methods.
Limitations: stratification is imperfect as strata cannot reflect all the ways in which people are different so complete representation is not possible.
Evaluate opportunity sampling.
Strength: quick method, convenient, cheapest method and therefore most popular.
Limitations: inevitably biased, sample is unrepresentative of the target population as it is drawn from a very specific area i.e sixth form common room, one street in one town so findings cannot be generalised.
Evaluate volunteer sampling.
Strength: participants are willing to take part so will engage more than other sampling method samples.
Limitations: volunteer bias…participants may share traits e.g. the desire to be helpful so generalisation may be limited.
