Research methods

• Stratified sampling

  1. Identify the strata

  2. Calculate the required proportion for each stratum based on the size of the target population

  3. Select the sample at random from each stratum

  4. Use a random selection method e.g. using a computer
• Sampling methods

  • Opportunity sampling
  • Random sampling
  • Systematic sampling
  • Stratified sampling
  • Volunteer sampling
• IV is the variable that is manipulated to observe its effect on the DV whereas the DV is the variable that is being measured and is affected by the IV
• Operationalisation


  The process by which a researcher defines how a concept is measured, observed, or manipulated within a particular study
• A solution to the problem of order effects caused by a repeated measures design is counterbalancing. This is when half of the participants are made to do conditions in one order and the other half in the opposite order, eliminating order effects
• One advantage of using a stratified sample is that the sample is able to be more representative of the target population compared to other types of sampling
• A directional hypothesis states the direction of the impact of independent variable (IV) on the dependent variable (DV) whereas non-directional does not state the direction of the relationship between the IV and the DV
• Explanation of the difference between the aim and the hypothesis
• Four types of experiments

  • Laboratory
  • Field
  • Quasi
  • Natural
• Explanation of two ways of assessing the validity of research
• Hypothesis


  A statement that predicts the relationship between the IV and the DV
• Problem of order effects caused by a repeated measures design

  Counterbalancing: Half of the participants do conditions in one order and the other half in the opposite order to eliminate order effects
• Main purposes of carrying out a peer review

  • To allocate research funding to worthwhile projects
  • To ensure research quality and relevance
  • To suggest improvements to prevent faulty or incorrect data release
• Limitations of conducting a case study
• Ways of assessing the validity of research

  • Face validity: Scrutinizing a measure for appearance
• Strengths of conducting a content analysis

  • High mundane realism and external validity
  • Produces a large data set of qualitative and quantitative data for easy analysis
• Limitations of conducting a case study

  • Not generalizable to wider populations
  • Relies on potentially unreliable memory in retrospective studies
  • Time-consuming
• Two types of skewed distributions

  • Positive skew - long tail on the right
  • Negative skew - long tail on the left
• Limitations of conducting a content analysis
• Aim of the study

  Tells us what the study is investigating
• Purpose of carrying out a peer review
• Limitations of conducting a content analysis

  • Causality cannot be established
  • Cannot extract deeper meaning or explanation for data patterns
• Strengths of conducting a content analysis
• Reliability

  A measure of consistency, for example, if a particular measurement is replicable, it is reliable
• Factors that help decide which inferential statistical test to use
• Example of concurrent validity
• Describe interval data and give an example
• Describe the difference between a single-blind procedure and a double-blind procedure

  In a double-blind procedure, neither the researcher nor the participant are aware of the aims, procedures and conditions of the study. In a single-blind procedure, it’s only the participant who isn't aware of them - the researcher is
• Describe nominal data and give an example
• Three levels of measurement

  • Nominal data
  • Interval data
  • Ordinal data
• Assessing the validity of research

  1. Face validity: A measure is scrutinised to determine whether it appears to measure what it is supposed to

  2. Concurrent validity: Checking the extent to which a psychological measure relates to an existing and well-established similar one
• Describe ordinal data and give an example
• Factors to decide which inferential statistical test to use

  • The level of data that was collected
  • Whether the design of the study is related or unrelated
  • Whether a difference or correlation is being measured
• Describe the difference between unstructured and structured observation

  An unstructured observation consists of continuous recording where everything the researcher sees is written down
• Unstructured observation


  • Consists of continuous recording where everything the researcher sees is written down
• Types of observation

  • Naturalistic
  • Controlled
  • Overt
  • Covert
  • Participant
  • Non-participant
• Things a researcher should think about when constructing a questionnaire

  • Clarity - ensure clear questions
  • Analysis - write questions for easy analysis
  • Sequencing questions - consider question order
• With correlations, variables are simply measured not manipulated
• Correlations do not involve a dependent variable (DV) or independent variable (IV), hence no cause and effect relationship is found, only an association
• Structured observation


  • Has a predetermined list of behaviors and sampling methods with which the researcher quantifies their observation