Define Population in terms of sampling
A group of people that are the focus of interest - a smaller sample is drawn from them
Define a sample
A group that is representative of the target population and thus take part in a investigation
Define a Random Sample
Where each member of the target popualtion has an equal opportunity of being picked
How would a random sample be carried out?
Lable all members of target population by numbers or letters
Using a number/letter generator, generate the desired amount of people for the sample
Define a Systematic Sample
When every nth member of the target population is selected
How would a Systematic Sample be carried out?
A sampling frame would be produced and then an interval for which the ppt will be picked is randomly generated
Define a Stratified Sample
When the sample reflects the proportions of people in each strata within the target population
How would a Stratified Sample be carried out?
- Identify each strata
- Work out representative proportions
- Ppts for each strata are randomly selected
Define an Opportunity Sample
Researchers picking ppts that are willing and available by simply asking people in the area
Define a Volunteer Sample
When ppt self-select themselves to be apart of the sample
How would a Volunteer Sample be optained?
By a researcher posting an AD stating they are looking for ppts
What are the strengths of Random Sampling?
- Free from researcher bias
What are the weaknesses of Random Sampling?
- Time-consuming
- Can still create an unrepresentative sample
- Ppts can refuse
What are the strengths of Systematic Sampling?
- No researcher bias
- Fairly Representative
What are the weaknesses of Systematic Sampling?
- Time consuming
What are the strengths of Stratified Sampling?
- No researcher bias
- Representative
What are the weaknesses of Stratified Sampling?
- Complete representation is not possible due to too many possible differences
- Time consuming
What are the strengths of Opportunity Sampling?
- Convenient
- Saves time and money
What are the limitations of Opportunity Samples?
- Researcher Bias
- Unrepresentative b/c from one area
What are the strengths of Volunteer Sampling?
- Easy
- Saves time
What are the limitations of Volunteer Sampling?
- Volunteer Bias; a particular ‘type’ of person may be attracted to take part
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Experimental Methods A112
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Control of Variables A112
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Experimental Design A115
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Experiment Types A113
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Sampling A121
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Ethical Issues A118
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Pilot Studies & Other ProceduresA18
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Observations Techniques and Design A18
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Self Report Methods and Techniques A118
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Correlations11
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Data Analysis26
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Features of a Science A218
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Reliability & Validity A221
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Content & Thematic Analysis AO1&AO3 A28
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Choosing a Statistical Test A223
