The big idea by which Data Desk works is to select the number of variables that goes with the operation you are performing.

Click (or Shift-Click) on a variable's icon to select it.

• Click on a variable's icon to make it a "Y" variable (the variable that will be plotted on a vertical axis when you include it in a two-variable graph).
  
  
  
  
  
  
• Shift-click on a variable's icon to make it an "X" variable (the variable that will be plotted on a horizontal axis when you include it in a two-variable graph).

For more information, consult the ActivStats printed guide (in your ActivStats box), or use Help or Index features of the ActivStats program.