Making Comparative Box Plots

2000-10-04

When you have groups of observations taken under different conditions, the best way to organize the data for analysis is to put all of the responses (y-values) in one column with the corresponding x-values beside them. For Q12-4, density of a brick is the response, and the firing temperature for that brick is the corresponding x-value.

To create the comparative box plot, just use density for the y-value and temp for the x-value in the box plot dialogue box.

  density      temp
      21.8       100
      21.9       100
      21.7       100
      21.6       100
      21.7       100
      21.5       100
      21.8       100
      21.7       125
      21.4       125
      21.5       125
      21.5       125
      21.9       150
      21.8       150
      21.8       150
      21.6       150
      21.5       150
      21.9       175
      21.7       175
      21.8       175
      21.7       175
      21.6       175
      21.8       175
Statistics 3N03