sampling

• what is population?


  a large group of individuals that a particular researcher is interesting in studying
• what is a target group?

  subset of the general population
• random sampling is a form of sampling in which all members of the target population have an equal chance of being selected
• systematic sampling is when every nth number of the target population is selected and a sample frame is produced
• a stratified sample is when the composition of a sample reflects the proportion of people in certain subgroups within the target population or wider population
• an opportunity sample is selecting anyone who happens to be willing and available the researchers ask whoever is around at the time of their study
• a volunteer sample is when participants select themselves to be part of the sample which is referred to as self selection
• random sample is potentially unbias
• random samples are difficult and time consuming
• random samples might end up with a sample that is unrepresentative
• systematic samples are objective
• systematic samples are time consuming
• stratified sample produces a representative sample because it is designed to accurately reflect the population
• an opportunity sample is conveniant
• opportunity samples are a lot less costly
• opportunity samples are unrepresentative of target population as it is drawn from a very specific area
• volunteer samples require minimal input from researcher
• volunteer samples are less time consuming
• volunteer samples have volunteer bias as asking for volunteers might attract certain profiles of people