Belief in UFO's, Ghosts, and Bigfoot

After putting in our data, we must subtract two from all intersections as 2 believe in all 3, so the intersection of UFO's and Bigfoot is 4 and the amount of people who believe in all 3 is 2, so we subtract 4 by 2 and thus find the intersect of UFO's and Bigfoot to be 2. We do this for all intersects and then add the amounts withing the intersect for each circle, for example, In those who believe in UFO's we add the intersects of those that believe in UFO's and Bigfoot with the amount that believe in UFO's and Ghosts, along with the value of those who believe in all 3. We then take that value and subtract it from the total who said they believe in UFO's. In this case, 42 people believe in UFO's, but the sum of all the intersections of those who believe in UFO's along with something else is 13. Therefore, we subtract 42 from 13 and get 29. We do this for all of the circles and get our results. Since 160 people were surveyed, we take the cardinality and subtract it from the unions, giving us 160-89, which equals 71 that believe in none. Therefore, 89 people believe in at least one of these things.