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Statistics and statistical graphs

What graph goes with what type of variable

Data can be organised and displayed in tables, graphs, or by a set of numbers describing the distribution.

  • The type of graph you use to display data depends on the type of data you are displaying.
  • If you are displaying one categorical variable you should use a bar graph or a pie graph.
    • Remember that pie graphs should only be used if all categories are present that is there is no category with zero responses.
  • If you are displaying one quantitative variable you should use either a histogram or a stem and leaf plot.
    • Remember stem and leaf plots are good for small quantities of data, while a histogram can be used with any size sample.
  • If you have two quantitative variables you should use a scatter plot.
  • If you have one quantitative variable and one categorical variable, you should draw a side by side box and whisker plot (boxplot).
  • Remember any graph showing percentages, should always show the sample size.