I’m not sure why it should disturb you. If the probability of intelligent life evolving in galaxy x is the same for all x, and there are about 100 billion galaxies in our observable universe, then the chance of intelligent life in the observable universe is about 1-(1-x)^100 billion. This assumes that whether life evolves in any one galaxy is independent of whether it evolved in another.
I wish I had remembered to use this formula when I took the survey.
I’m not sure why it should disturb you. If the probability of intelligent life evolving in galaxy x is the same for all x, and there are about 100 billion galaxies in our observable universe, then the chance of intelligent life in the observable universe is about 1-(1-x)^100 billion. This assumes that whether life evolves in any one galaxy is independent of whether it evolved in another.
I wish I had remembered to use this formula when I took the survey.