Are you more likely to be selected for Delta Force as a ranger or a Green Beret?

More likely to be asked to try out for Selection, yes, but still very small chances of making it in. Each year, Delta goes over Army records for the best Green Berets and Rangers, and ask them to try out for Delta Selection. Only the top 0.1% of those asked will actually make it through and be accepted. You have a much higher probability of making it into the NFL or NBA than making it into Delta Force. After a candidate is admitted into the unit, they then undergo years of more specialized and rigorous training. If you're a regular Army soldier, you may be asked to try out for Delta Selection, but you really have to be an extraordinary standout for them to notice you. You can't just sign up somewhere, they ask you; and they're mostly looking and Green Berets and Rangers because they know that they are the best.