# Sampling Methods

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• Created by: Emily
• Created on: 21-05-13 14:41
• Sampling Methods
• Volunteer Sampling
• Individuals who have chosen to take pert in the study - may have responded to an advert
• ++ Quick and economical, common and informed consent already given
• -- Unrepresentative only a certain type of people will put themselves forward, who will see the advert
• Random sampling
• aksing people in the street, pulling names out of a hat ect
• ++ large samples provides unbiased results everyone has chances of selection
• -- time consuming, too small sample leads to bias
• Stratified and Quota Sampling
• Diving the population into important sub categories then selecting 25% of those
• ++ Representitive of the target population  - equal from subgroups
• -- can be time consuming, has to be quite a large sample size
• Systematic sampling
• all participants in a list every 10th person is chosen
• ++ unbiased system
• -- if one person says no the whole system breaks down
• Opportunity Sampling
• Sampling Methods
• Volunteer Sampling
• Individuals who have chosen to take pert in the study - may have responded to an advert
• ++ Quick and economical, common and informed consent already given
• -- Unrepresentative only a certain type of people will put themselves forward, who will see the advert
• Random sampling
• aksing people in the street, pulling names out of a hat ect
• ++ large samples provides unbiased results everyone has chances of selection
• -- time consuming, too small sample leads to bias
• Stratified and Quota Sampling
• Diving the population into important sub categories then selecting 25% of those
• ++ Representitive of the target population  - equal from subgroups
• -- can be time consuming, has to be quite a large sample size
• Systematic sampling
• all participants in a list every 10th person is chosen
• ++ unbiased system
• -- if one person says no the whole system breaks down
• Taking a sample from people who are available at the time. Stopping pupils in the corridor or going into a year 7 classroom
• ++ convenient and ethical. Wide variety of ppts leading to a representative
• -- Unrepesentitive samples can be bias as we are likely to choose helpful looking people. Only a subgroup of the target population
• Sampling method
• Sampling method description and eg
• positives
• negatives