Answer:
Yes, that's correct. In probability theory, the sum of all probabilities within a particular sample space or for a specific event must equal one. This fundamental principle reflects the certainty that some outcome will occur when dealing with all possible outcomes. In other words, when you consider all the possible events or outcomes, the total probability of those events happening is 100% or 1. This principle ensures that probabilities are properly normalized and consistent within the context of probability theory.