I would suggest that you expect your beliefs to be changed in 100% of cases. Currently, you believe in a 50% probability. After doing the tests, we have a set of universes, some of in which you believe a 100% probability and some of in which you believe a 0% probability. Your belief changed in every single one.
X and Y can be averaged out, but belief in number X and belief in number Y don’t average out to be “belief in the average of X and Y”.
I would suggest that you expect your beliefs to be changed in 100% of cases. Currently, you believe in a 50% probability. After doing the tests, we have a set of universes, some of in which you believe a 100% probability and some of in which you believe a 0% probability. Your belief changed in every single one.
X and Y can be averaged out, but belief in number X and belief in number Y don’t average out to be “belief in the average of X and Y”.