research methods

• aim


  statement outlining the purpose of the investigation
• research hypothesis

  testable prediction of the relationship between two or more variables
• hypothesis

  formula: population, IV, direction + DV, IV
• independent variable

  manipulated variable
• dependent variable

  measured variable
• population

  entire group of research interest
• sample


  a part of the population
• random sampling

  when every member of the population has an equal chance of being selected for the sample

  • benefits: reduce bias for large groups
  • limitations time consuming. smaller groups may not be representative.
• convenience sampling

  selection using the quickest and easiest means possible.

  • benefits: time and cost efficient
  • limitations: likely to be not representative of the population
• stratified sampling

  when the population is divided into groups based upon characteristics.

  • benefits: more likely to be representative of the population.
  • limitations:
  • time-consuming and expensive to ensure strata is accurate.
  • strata can be difficult to define
• between subjects

  each participant is randomly allocated to one condition only.
• within subjects


  each participant is involved in all conditions providing multiple scores.
• between group design

  strengths:

  • cost effective
  • efficient
  • experiment doesnt need to be repeated

  limitations:

  • participant differences can affect results
• within group design

  strengths:

  • fewer participants
  • eliminates differences

  limitations

  • order effects
• mixed design

  combines between and within subject designs