Participants

• Evaluation - strengths and weaknesses
• Target population - group of individuals researcher is interested in. Sampling frame - smaller group from target population. Sample group - participants in research.
• Random sampling - list of people in population then use a random name generator such as names in a hat. Advantages - unbiased, less chance of researcher bias. Disadvantages - time consuming and may still be biased.
• Opportunity sampling - choosing people who are available at the time Advantages - quick and easier, appropriate when sampling frame is unknown. Disadvantages - increased chance of researcher bias, biased sample.
• Systematic sampling - using a pre-determined system for example every nth person. Advantages - less chance of bias, quick sampling technique. Disadvantages - still may be a biased result, not practical when sampling frame is unknown.
• Self selected sampling - advertise for ppts on the internet or a notice board. Advantages - more ethical than other sampling techniques, quick and easy sampling method. Disadvantages - prone to volunteer bias, more likely to get demand characteristics.
• Quota sampling - subgroups within a target population are identified and ppts gained from a pre-set numbers from each strata. Selection from non-random opportunity. Advantages - 2nd most representative sampling method, quicker than using stratified sampling. Disadvantages - time consuming, could still contain researcher bias.
• Stratified sampling - subgroups identified ppts gained from each strata, then a random sampling technique. Advantages - most representative sampling method, less chance of researcher bias. Disadvantages - time consuming, could still be some bias.
• Snowball sampling - find one ppt then the recruit other ppt, such as people they know. Advantages - can access difficult to reach ppts, appropriate when sampling frame is unknown. Disadvantages - not representative may difficult to generalise the findings of the target population, time consuming, need to wait for participants to refer other participants.
• Generalisation - applying the findings of a particular study to target population.
• Representative - proportionately representing all sub groups in the sampling frame.
• Biased sample - some have a higher/lower probability of being chosen.