How to hide a sub-report if it has no data?

I have a sub-report within a master-report that at times does not have any data to display for the linked master-report.  Due to some graphics I have in the sub-report, the sub-report displays at all times, but I would like to hide the sub-report (turn off its visibility) during those occasions where there is no data.  I have a text box in the master-report that indicates true/false if the sub-report is empty (has no data).  I know I want to do some kind of macro or if else statement to turn the sub-report's visibility on and off.  I just don't know how...

The master-report is called: R_Activities_sub1
The sub-report is called: R_Activities_sub2
The true/false textbox in the master-report is called: subgood