IQR range in boxplot I'm having a look at altair docs, and I don't understand why, in the last two groups (85 and 90), that have a very low IQR, they have similar whiskers than in the first group, where the IQR of the first group is huge. What am I missing? Why do the two last groups have such long lines?


This is probably because the distribution is heavily skewed for higher ages. The Y-axis appears to be a count (number of people), which is by definition bounded at zero because you cannot have a negative number of people.
For the highest age categories, the minimum, first quartile and median are very close to each other because there are many entities (states?) with very few old people. But there is at least one (and probably a few) entities that do have a lot of old people, which is why the upper whisker is fairly long.
Plotting these as violin plots or (sideways) histograms would make the pattern clearer by showing the full distributions.
