Hi,
The label OverAverage is right at the bottom of the code you just posted.
Usually you include the file somewhere around the top of your program. When the program starts from the beginning it eventually reaches the code which is in the include file. If you don't want it to execute the code at that point you must jump over it and that's exactly what's happening here.

Then, when you actually WANT to execute the code from within your main routine or whatever you GOSUB Average, that way it will enter the code after the GOTO OverAverage and execute the code until it hits the RETURN which returns the execution to the place it was called from.

/Henrik.