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Sampling - Coggle Diagram
Sampling
Random
Every member of target population has en equal chance of being selected - obtains names of everyone and either used manual selection (names pulled out of a hat) or computer selection.
(+) No researcher bias: everyone has equal chance of being selected - cannot select who will get answers
(+) Sample is likely to be representative of target population: equal chance of being selected - different types of people but (-) may not be representative of target population: people will similar characteristics may be given
(-) Time consuming: Writing down and identifying all members of the target population - especially if large
(-) Sample may not be truly random: some may not consent to be part of study - only one type of person
Systematic
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(+) No researcher bias: no control who is every nth member - not likely to choose who will support hypothesis
(+) Sample is likely to be representative of the target population: entire target population is being chosen from but (-) sample may not be representative of target population: you cannot guarantee that everyone will be different
(-) Time consuming: Long time to identify and write down all the members of the target population - especially if population is big - take a lot of time and money
(-) May not select willing participants: not all participants may want to take place in the study - will have to do a further systematic sample
Stratified
Mirrors the target population so the proportions of each sub group are the same in the target population and he sample.
Identifies the different sub-groups and calculates the number of each subgroups required for the sample - equal amounts
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(+) Sample is highly likely to be representative of the target population: highly likely to represent all the different types of people in the target population
(-) Time consuming: Takes along time to identify all the different sub-groups especially if target population is big and diverse - many different characteristics to consider.
Opportunity
Taken using any convenient members of the target population who are willing to take place in the study.
(+) Not time consuming: Convenient and accessible members of the target population - saves time and money
(-) Researcher bias could occur: may influence who takes part - who are likely to produce the results that will support hypothesis.
(-) Sample may not be representative of the target population - low population validity: people may not be representative of all the different people in target population
Volunteer
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(-) Sample may not be representative of all the target population - low population validity: may not be representative of all the people in the target population.
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Sample: Psychologists must chose who to study in their research because they cannot do the whole target population
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