I don't think we actually know the answer to this question. How can you be sure you've already decided before it's visualized? How do you know that it isn't decided at the same time it's visualized? Try looking at the dice after rolling, then look away, then look again. Is it the same number? When you do this with text, very often it will not be the same text on the second look.
Can I just point out that if we use this logic, nothing in a dream is premeditated and you would be going against the whole idea that science has of how we think up dreams. You don’t consciously know what is going to happen in (normal, not talking lucid or anything) dreams it’s the exact same thing, the number has to come from somewhere in your conscious just like the dream sequence has to come from somewhere otherwise the whole thing would just be a series of illogical events and no story line.
I'm not saying that a dream is random at all. I'm merely pointing out that we don't know for certain the order of events within the brain. If you can cite a study confirming an order of events then I would be very interested indeed.
There's no way to determine wether a number is pre determined, random, or freely picked. Choose a number between 1-1000. Ok, why did you choose that number? If there is no free will or every effect has a cause, you can't choose a random number. If there is free will, and you don't know why you chose a number it is random to you. If I can't readily guess it or predict it then it is random to me.
Since we have no way to know how much is predermined in the universe, or if free will even exists, we can't say that randomness does or does not exist either. True to say that even in science the idea of randomness in nature is just a theory and not proven the case. As a creation of your mind the numbers you see in a dream would follow as random or static as anything else in the universe may be. But for all intents they could be random to you the observer.
Ooo I wonder what effect this also has on observational theories that something is only in that state or position because we are observing it. Does it being in our minds/dreams mean we are seeing its relative position in our own universe or another? If none at all then that would prove thought is something like a quantum effect.
You mean roll the die? The answer is of course yes. Random in the fact that you may not know the answer but predetermined because the brain uses actual memories to make your dreams. Chances are you've already seen that specific roll of the die you just don't remember it or the outcome but your subconscious does.
Since we have no way to know how much is predermined in the universe, or if free will even exists, we can't say that randomness does or does not exist either. True to say that even in science the idea of randomness in nature is just a theory and not proven the case. As a creation of your mind the numbers you see in a dream would follow as random or static as anything else in the universe may be. But for all intents they could be random to you the observer.