Completely different.
A 50-50 event would be something like a coin toss. Before you toss the coin, you have a 50% chance of either heads or tails. After you flip the coin (even if you don't look at it), it's either heads or it's tails and probabilities are essentially meaningless. Either it happened or it did not.
Let's say there is a town with 1000 people. 25 of them get attacked in one month. You can conclude that the probability of a person getting attacked during a one month period is 25/1000 = 2.5%. That only applies to the population, helping to predict what might happen to randomly selected people. However, once you pick an individual, you have changed everything. They are now your entire sample and the probability that applied to the entire population no longer applies.
Let's call that individual Mike. Mike will either be attacked or Mike will not be attacked, so the probability is either 1 (attacked) or 0 (not attacked). Mike can't be 2.5% attacked. What you can say, however, is that Mike is a member of a population which has a probability of 2.5% of being attacked. It may seem like semantics or splitting hairs, but it's a fundamentally different situation when discussing individuals vs. populations.
The medical/health professionals are among the worst at either failing to understand this or purposely choosing to make factually incorrect statements (perhaps for expediency because they believe the nuances will be lost on their audience). For example, let say the mortality rate within 6 month for cancer A is 25% in the population. A patient who is diagnosed with this cancer is already selected from the population. She asks the doctor what her chance of dying within 6 months is. .
The doctor then has some choices. The doctor can be correct and say something like, "I can't predict what will happen to you, but I can say that of everyone who has your condition, 25% of them die within 6 months." Or, the doctor can be either ignorant or lazy and tell the patient they have a 25% chance of dying within six months, which is not a factually correct statement. Clearly patients demand and expect "numbers" sometimes, but it would be better for the doctor to avoid misinterpretation of probabilities and find a way to express the ideas to the patient in a way they can understand, but is not misleading.
I'm not sure that helps. My inability to explain clearly and concisely suggests that my own understanding of the concepts is inadequate! That, of course, begs the question: why the hell did rhino open his big virtual mouth? Answer: he lacks the ability to remain silent.
