Astonishing
Astonishing
No, this is how a graph showing quartiles will always look because quartiles, by definition, always include a fixed percentage of the studied population under them.
In this case the lower quartile will always have 25% of the population under it, 50% under the second quartile, and 75% under the third quartile.
Quartiles break a population into 4 equal portions.
Yes I think it’s very possible that if you were to graph a population’s Intelligence using a some empirical score, then it has a high probability to NOT look exactly like a normal distribution.
For example, let’s say that there was some score called “intelligence score” that scores people’s intelligence from 0-100. Do you think that if you were to graph a given population’s “intelligence score” that it would be EXACTLY centered around 50 in a Normal distribution? I think that’s unlikely. It’s more likely that there would be local maximums or minimums, or various skews in the graph. There could be a small peak at score 75, or a trough at 85. There could be all sorts of distributions. And guess what? Given this hypothetical distribution, you could STILL draw lines somewhere on the graph showing quartiles.
In fact, all kinds of distributions can be broken into quartiles, not just normal distributions.