The average co2 tonnes per capita is not the typical one

Every skewed column has the same conversation attached to it, so here it is once, on co2_tonnes_per_capita in world-indicators.

The mean is 3.67. The median is 2.80. That is a gap of 31.1%, and it is not noise — the p90 is 7.50 and the max is 15.49, so the top of the distribution is dragging the average somewhere a minority of rows actually live.

select
  avg(co2_tonnes_per_capita)                                                     as mean,
  percentile_cont(0.5) within group (order by co2_tonnes_per_capita)             as median,
  percentile_cont(0.9) within group (order by co2_tonnes_per_capita)             as p90,
  max(co2_tonnes_per_capita)                                                     as max
from world_indicators;

The practical consequence is that "average co2 tonnes per capita" answers a question nobody asked. If someone wants to know what a typical row looks like, the median answers it. If someone is forecasting a total, the mean is the right tool and the skew does not matter, because the mean times the count is the total.

So the rule is not "never use the mean". It is: name which question you are answering, then pick the statistic that answers it. A report that shows 3.67 with no median next to it has quietly decided you meant the first question.

There is a longer version of this in Describing a column without lying, and the pattern is the short one.