Since it takes a while to get the IOLab (device uncertainty 3%) swinging the way you want it, and then some time to wind down before you hit Stop, only some of the graph is relevant for determining the average force acting on the IOLab during uniform circular motion. Selecting the relevant part of the F-t graph using the Histogram Tool (i.e., the area where the IOLab was moving in uniform circular motion) the above example appears something like this:

Force (4800 Hz) At: 24.95874 s U: -4.471 N - o: 0.58 N a: -111.59 Ns s: 0.04 N/s (r : 0.29) GO N -2 Fy (N) -6 -8 -10+ 15 20 25 30 35 0 5 10 Time (s) Rezero sensor