sampling

• Sampling is the process of selecting a subset of the population to be studied.
• The population is the entire set of people the researcher wants to research
• A sample is the chosen group of people, from the population, to take part in the study/experiment.
• random sampling is when every member of the population has an equal chance of being selected.

  
• Systematic sampling is when the researcher collects the nth number out of an organised list of the whole population.

  
• stratified sampling is when the sample is a direct reflection of the target population.

  
• opportunity sampling is when researchers get their sample from those who available at the time of the study.

  
• Volunteer sampling is when the researcher allows for people to 'self-select' themselves to take part in the study.

  
• disadvantages of random sampling

  Time consuming to gather a whole list
• Advantages of random sampling

  Can more representative than opportunity and volunteer.

  Avoids researcher bias
• Disadvantages of volunteer sampling

  volunteer bias - as certain types of people will sign up for things.
• advantages of volunteer sampling

  Least time consuming method

  ca reach a wider audience (depends)
• advantages of Systematic sampling

  Avoids researcher bias

  fairly representative
• disadvantages of systematic sampling

  can take time to conduct
• advantages of stratified sampling

  Highly representative - as is made to reflect the population

  avoids researcher bias as randomisation happens after sample is organised into a the strata
• disadvantages of stratified

  Can not match all the the ways that people are different so full representation isn't possible. Time consuming
• advantage of opportunity

  It is convenient - as it doesn't take as long as the systematic or random
• disadvantages of opportunity

  It is the least representative - this is the sample is from one geographical area or time of day.

  researcher bias - as the researcher has complete control over what pps to chose