Sampling

• An opportunity sample uses whoever is conveniently available.
• Strengths of an opportunity sample is it is time saving and less cost.
• Limitations of an opportunity sample is it is not representative as it is not random and there may be researcher bias.
• Volunteer sampling is when the researcher selects participants from a pool of self selected people.
• Strengths of a volunteer sample is it is easy and not time consuming. Volunteers also may be more cooperative.
• A random sampling allows all members to have an equal chance of being selected.
• Strengths of a random sample is there is no researcher bias and is usually representative.
• Limitations of random sampling is that it is time consuming and expensive. It still may not be represented as people have to agree to take part.
• Systematic sampling is when every nth person is selected from the sampling frame.
• Strengths of systematic sampling is it avoids researcher bias and is usually representative.
• Limitations of stratified sampling is that it is time consuming. It is not truly unbiased unless random sampling starts the systematic sample.
• Stratified sampling is when the composition of the sample reflects the varying proportions of people in sub groups within the wider population.
• Strengths of stratified sampling is there is no researcher bias and it is representative.
• Limitations of stratified sampling is it is time consuming and the identified strata cannot reflect the differences between people.