presentation of quantitative data

• Tables and graphs

  • Tables
  • Bar charts
  • Histograms
  • Scattergrams
• distributions

  • Describe how quantitative data values are spread or clustered across possible values
  • Normal distribution =  bell-shaped curve - most items are in the middle area of the curve with very few at the extreme ends
  • The mean, median and mode all occupy the same mid-point of the curve.
  • Skewed distributions =  distributions that lean to one side or the other because most items are either at the lower or upper end of the distribution (mode is highest point of peak, then median, then mean)
  • Negative skew = most of the distribution is concentrated towards the right of the graph, resulting in a long tail to the left
  • Positive skew = most of the distribution is concentrated towards the left of the graph, resulting in a long tail on the right
• Normal distribution

  
• Negatively skewed distribution

  
• positively skewed distribution

  
• Bar chart

  • Display categorical/discrete quantitative data
  • Useful for comparing values across categories
  • Bars separated by gaps
• tables

  • Organise detailed/complex numerical data
  • Allow for presentation of exact values (easy to analyse/compare data points)
• Histograms

  • Visualise the distribution of continuous numeric data by grouping values into intervals and plotting the frequency of data
  • Bars touch each other - reflects the continuos nature of the data
• scattergrams

  • Plot individual data points to show the relationship between 2 quantitative variables
  • Useful for identifying correlations, trends and patterns between variables