Sampling

• Sampling-

  Finding a smaller part of the target population to be experimented on, often having some sort of bias in it, but is used to try and achieve generalisable results.
• Random sampling-

  • Sophisticated form of sampling where all members of the target population have equal chances of being selected.
  • Firstly, a list of all the members is made.
  • Then the names are assigned numbers.
  • A sample is then generated through the use of a lottery method on a computer or picking from a hat.
• Random sampling-

  • S- High internal validity due to being unbiased.
  • W- Time-consuming to conduct.
  • W- Participants may refuse.
• Systematic sampling-

  • Participants are chosen mathematically.
  • Using the nth person in the sampling fame for the sample.
  • Through the listing of the sampling frame into alphabetical order then selecting the person every nth number.
  • Keeping the nth number the same and selecting people until the sample is complete.
• Systematic sampling-

  • S- No influence on who’s chosen once the system is established.
  • W- Time consuming.
  • W- Participants may refuse.
• Stratified sampling-

  • Sampling frame is divided into groups (strata) that the researcher wants to make sure are represented in the experiment.
  • Then a number of participants from each group is selected, ensuring that each group is proportionally represented in the sample.
• Stratified sampling-

  • S- Accurately designed to represent the composition of the population.
  • W- Can’t reflect all the ways people are different.
• Opportunity sampling-

  • Participants are chosen due to convenience 
  • Selected because they have: actively volunteered, local, known to the researcher.
• Opportunity sampling- evaluations

  • S- Less costly in time and money due to being random and convenient.
  • W- Unrepresentative of the whole population due to being from a certain area.
  • W- Selection may be controlled, by avoiding people on purpose.
• Volunteer sampling-

  • Self-selecting sample as participants volunteer themselves to be [art of the research].
• Volunteer sampling- evaluations

  • S- Simple due to the researcher not having to do Anyang to obtain participants.
  • S- Participants are more engaged.
  • W- May attract a certain ‘profile’ of people who are curious and possibly more likely to try to please the researcher.