Double-click the column name to which you want to apply the formula, select Formula from the Column Properties menu, and then click Edit Formula.
When you type, a small text editor window appears, which enables you to edit the formula. You can click the Maximize editor button if you need more room. Long formulas open in the maximized editor by default.
Figure 6.2 Building a Formula
See Use Basic Formula Editor Features, for an example of how to use the Formula Editor.
Notes: 
You can also use the Formula Editor to define a custom format. For example, you might want to convert a number from inches to centimeters using the calculation Char( :height * 2.54 ) || " cm". Realize that the underlying data, which you see when double-clicking a data table cell, would still be the value of :height.
:Y - Col Mean( If( :Status == "nonsmoker", :Y, . ), :Cycle )
In a new Y2 column, create this formula:
If( :Status == "nonsmoker",
	:Y,
	.
)
:Y - Col Mean( :Name( :Y2, :Cycle )

Help created on 7/12/2018