Sampling

• Target Population- Every member of the group that the investigation plans to study
• Representation- Sample used in the study shares characteristics of the members in the target population
• Random Sampling is when everyone has an equal chance of being selected for the study
• Random Sampling pro:

  1. avoids researcher bias
• Random Sampling con:

  1. could pick an unrepresentative sample
  2. time consuming (sometimes)
• Systematic Sampling is when participants are chosen form a list of the target population
• Systematic Sampling pro:

  1. avoids researcher bias
  2. can be quick is there is a pre existing list
• Systematic Sampling con:

  1. unrepresentative
  2. large population may result in difficulty
• Opportunity sampling is when researchers ask members of the target population directly
• Opportunity sampling pro:

  1. convenient
• Opportunity sampling con:

  1. unrepresentative
  2. may result in researcher bias
• Volunteer Sampling is when participants offer to take part in the research
• Volunteer Sampling pro:

  1. collection large number of participants
  2. easy
• Volunteer Sampling con:

  1. may not be generalisable
  2. volunteer bias
• Stratified Sampling is when participants are selected equally from each strata (smaller sub groups)
• Stratified Sampling pro:

  1. representative and therefor generalisable
  2. avoids researcher bias
• Stratified Sampling con:

  1. not every characteristic will be included which could arguably lead to bias
  2. time consuming