An equation statistic is a statistic which computes its values based on a mathematical formula using the values of other statistics.
In the first page of the Statistics Wizard enter the name and abbreviation, then select the Equation option for the Stat/Graph Type as shown by 
.
In this example, we'll create a Total Sales statistic which adds the statistics Sales US and Sales Europe.
Set the options you want on the second page of the wizard. Click Next.
When the Equation option is selected, a third page becomes active.
In our example there is no defined equation yet, so click the Add Equation button as shown by 
. The Management by Statistics system allows you to define different equations covering different time periods.
An equation window will appear.
First set the date the equation should start calculating from as shown by 
. If you have values which go back two years, then the start date should reflect this.
Next use the Add Statistic button and other buttons to create your equation as shown by 
When selecting a statistic to include in your equation it can be from any company you have set up in the software as shown by 
Complete the equation to do the calculation you want as shown by 
Click OK to save the equation, then click Finish to close the Statistic Wizard.
From this point forward when a value is entered for Sales US or Sales Europe the value for Total Sales will be recalculated automatically.
NOTE: Equations require a value for each statistic used in the equation before a calculation is performed. If you do not enter a value for Sales US on a given day, the calculation will not be done. The system does not assume a missing value is zero. If a statistic value is zero, enter a zero.