Roosevelt is smart enough to not gamble their own life on the question, and ultimetly, your odds of having a higher IQ than Roosevelt is 50%; you probably have a triple digit IQ, but so does Roosevelt as do all frequent users on this site.
Maybe lower the stakes; whoever has the lower IQ out of you and Roosevent has to venmo $5 or something like that to the winner.
And how would you make your IQ publicly testable. I can say my IQ is 164; there is no way to prove I'm wrong. You can then say your IQ is 172; again; no way of proving you are wrong even if you would be (majority chance).