Your decisions themselves do affect events. For an example for all those nasty viruses or diseases out there, scientists and doctors have discovered medicines and cures/vaccines for those illnesses. If none of those doctors/scientists did anything, the world wouldnt be where it is now.
It was the free will of those doctors/scientists to go down the path they took to find solutions for the problems that happened in the past. If they did nothing and left random chance, I doubt any of us would be alive or lived long enough to post here.
Now it is because of randomness, that it takes time for those cures/vaccines to be made which is why I believe randomness and free will go hand in hand together. Randomness in this case could be anything at this point, whether it could be existance of needed materials/supplies, funding for the research, or lab accidents, etc.