C_J technically that’s only true under a very specific set of conditions that you wouldn’t expect to hold in the real world, i.e. a perfectly symmetrical, normally distributed mesokurtic data set.
What he’s really talking about here is the median - but that joke would be lost on the average audience I guess 🤷🏻♂️/Hugo]
Lol, yes well for one thing it will depend on how you’re measuring stupidity/intelligence. It also depends on what population you’re considering.
An obvious example might be a typical IQ test, though the results of those are as you suggest typically normalised to a perfectly symmetrical standard distribution. It’s actually surprisingly difficult to find studies which monitor the IQ of a sizeable population and show how the results are distributed without being normalised.
However, I did find these two papers which appear to be among the most thorough studies out there and which also appear to come to similar conclusions to each other at least with regards to the averages and skew. They’re also both based on data from the UK.
TLDR - it appears IQ is pretty close to a standard/symmetrical distribution, but with a slight negative skew. i.e. the tail of “idiots” is slightly longer than that of “geniuses”. So if as per the joke you did pick the median average person on the street (the person at the half-way mark if you lined all the humans in a row) they would actually be a teensy bit more intelligent than the mean average intelligence of all the population.
So the mean average would still be around 100, but the median average person will be slightly higher at an estimate of maybe 101-102, and the modal average (the most common inidividual result) of maybe 105.
I’ve added the graph below it from wiki to help you visualise where the drawing of the mean, median and mode lines would fall on such a chart considering my points above and the apparent negative skew of IQ (but the size of the skew in the illustration is a bit larger/less symmetrical than what is probably the case).
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.880.6529&rep=rep1&type=pdf
https://www.abelard.org/burt/burt-ie.asp
Final point - to reiterate the above are focused on studies of the UK, where the mean average is about 100. Different countries will have a different population average IQ, but the shape of the curve could well be consistent across different populations.
PS I’m aware this isn’t that funny.
