In theory the outcome of this experiment was supposed to be exactly 1/2, but the outcome was not 1/2. The result of the 20 flip trial was 9/20, which can't be simplified. The result of the 50 flip trial was 28/50, which can't be simplified. The result of the 100 flip trial was 49/100, which can't be simplified. They outcomes of all of them were close to 1/2, but none of them were exact.