I wonder how much of this is innumeracy rather than mis estimation. What I mean is that people may actually intuitively understand more accurate proportions, bu

I wonder how much of this is innumeracy rather than mis estimation. What I mean is that people may actually intuitively understand more accurate proportions, but due to lack of education they don’t understand how to convert that to percentages. That may not even be due to not understanding the math itself (ie 1/5 is 20% and 1/100 is 1%) but perhaps not linking the two concepts, so they don’t even think in terms of their intuition when asked to give a percentage. Part of the reason why I suspect this is that even the smallest groups are measured at close to 20%. But I bet the average person knows the groups are rare or very rare, just not what 20% actually means in terms of rarity