The data set can include all of the data in a DATACOL object, or a subset of the data in a DATACOL object.
DataCol 
DATACOL 
The column of data upon which to calculate the mean. 

FirstPoint 
INDEX 
The first point to include in the data set (Optional) 

LastPoint  INDEX  The last point to include in the data set (Optional)  
Result  REAL 
The Mean of the DataCol Sum(x)/N 