In order to calculate the probability that a randomly selected female student from a school plays either softball or soccer, we would need to know two critical pieces of information:
1. The total number of female students in the school. This would be our denominator or total possible outcomes.
2. The total number of female students who play either softball or soccer. This would be our numerator or preferred outcomes.
However, these details are missing from the question. Without it, we cannot calculate the required probability.
Hence, based on the information given, we can't solve this problem.