Kind of. The p-value is derived from the measurements we have already taken. So I would rephrase your rephrasing as: Taking a simpler example: I have a coin in my pocket that I think is biased towards coming up heads. The null hypothesis is that it is fair and has an equal probability of coming up heads or tails. I toss the coin six times. It comes up heads five times. My p-value is the probability that, if the null hypothesis is correct, I got the result I did - i.e. if the coin is fair, what is the probability of getting at least five heads upon six coin tosses.