Research Methods

• Hypothesis


  A testable statement predicting the relationship between variables
• Null hypothesis


  States there is no effect or relationship
• Alternative hypothesis


  States there is an effect or relationship
• Independent variable (IV)


  The variable that is manipulated by the researcher
• Dependent variable (DV)


  The variable that is measured to see if it is affected by changes in the IV
• Operationalisation

  Defining variables in practical, measurable terms
• Types of experimental designs

  • Independent groups design
  • Repeated measures design
  • Matched pairs design
• Independent groups design


  Different participants are used in each condition of the experiment
• Repeated measures design


  The same participants are used in all conditions of the experiment
• Matched pairs design


  Pairs of participants are matched on certain characteristics, with one member of each pair assigned to each condition
• Main types of data collection methods

  • Self-report
  • Observational
  • Experimental
• Self-report method


  Participants provide information about themselves, typically through questionnaires or interviews
• Types of observation


  • Naturalistic observation
  • Controlled observation
• Naturalistic observation


  Observing behavior in its natural environment without interference
• Controlled observation


  Observing behavior in a controlled setting where variables can be manipulated
• Case study


  An in-depth investigation of an individual, group, or event
• Correlation


  A measure of the relationship between two variables
• Positive correlation


  Both variables increase together
• Negative correlation


  One variable increases as the other decreases
• Strengths and weaknesses of using correlations

  • Strengths: Can identify relationships between variables
  • Weaknesses: Cannot establish causation
• Random sampling


  Every member of the population has an equal chance of being selected
• Stratified sampling


  The population is divided into subgroups (strata), and random samples are taken from each strata in proportion to their prevalence in the population
• Opportunity sampling


  Participants are selected based on availability and willingness to take part
• Volunteer sampling


  Participants self-select to be part of the study, often in response to an advertisement
• Reliability


  The consistency of a research study or measuring test
• Types of reliability


  • Internal reliability (consistency within the test)
  • External reliability (consistency over time)
• Validity


  The extent to which a test measures what it claims to measure
• Types of validity


  • Internal validity (extent to which the results are due to the IV)
  • External validity (extent to which findings can be generalized)
• Ecological validity


  The extent to which research findings can be generalized to real-life settings
• Pilot study


  A small-scale study conducted to refine the methodology before the main research
• Ethical considerations in psychological research

  • Informed consent
  • Deception
  • Protection from harm
  • Confidentiality
  • The right to withdraw
• Informed consent


  Participants are fully informed about the nature of the study and agree to participate
• Deception in research


  Misleading participants about the true purpose of the study
• Protection from harm


  Researchers must ensure participants are not physically or psychologically harmed
• Confidentiality


  Ensuring that participants' data is kept private and anonymous
• Right to withdraw


  Participants can leave the study at any time without penalty
• Quasi-experiment


  An experiment where the IV is not manipulated by the researcher but occurs naturally
• Laboratory experiment


  An experiment conducted in a controlled environment where the researcher manipulates the IV
• Field experiment


  An experiment conducted in a natural setting where the researcher manipulates the IV
• Natural experiment


  An experiment where the IV is a naturally occurring event and the researcher observes the effect on the DV