Graphical Representations

• Graphs

  • Histogram:
  • Continuous interval/ratio
  • No gaps
  • Y-axis frequency
  • Line Graph:
  • Frequency polygon
  • Clear comparison
  • Ideal for many IVs
  • Bar Graph:
  • Discrete categorised (nominal)
  • Separate, same width
  • X-axis categories
  • Many sets
  • Uses central tendency measures
  • Scatter Graphs:
  • Shows correlational strength and direction
  • Determined by correlation coefficient
  • Curvilinear Correlations:
  • Coefficient ~0
  • Initial positive, then negative (inverted U)
  • Initial negative, then positive (U)
  • Tables:
  • Summarises and presents data visually
  • Central tendency and dispersion measures
• Graphical Representations

  • Visually depict data patterns
  • Histograms, line graphs, and bar charts show variable differences
  • Scatter graphs show variable relationships
  • Clear, raw results are in appendices
  • IV on horizontal axis (x)
  • DV on vertical axis (y)
  • Titled and correctly labelled with clear key
  • Must follow UP RAT
  • Units
  • Pencil
  • Ruler
  • Axis
  • Title
  • Sense-checking is crucial to ensure statistical tests show significant differences/correlations
• Problems with Graphs

  • Y-axis starting at high number can distort graph
  • Small changes appear larger
  • Context is crucial in comparison
  • Bar graphs preferred in psychology
  • Small changes/trends look larger
  • E.g due to different sample sizes
  • X-axis can be manipulated to distort data
  • E.g. how bars are grouped/spaced
  • Appearance and narrative change dependant on where y-axis starts and how x-axis is grouped or divided