The point is that, on the left, the two groups look about the same to the eye at first glance.
In left examples the numbers are off by a factor of 7/6 or less vs. in right examples the numbers are off by a factor of 2 or greater.
Specifically, in left examples the numbers are off by a factor of 7/6 or less vs. in right examples the numbers are off by a factor of 2 or greater.
The numbers of dots in the two clusters are approximately equal (log scale) vs. the numbers of dots in the two clusters differ a lot.
Specifically, the numbers differ by less than a factor of 2 vs. the numbers differ by a factor of 2 or greater.
The numbers of dots in the two clusters are approximately equal vs. the numbers of dots in the two clusters differ a lot.
Aaron David Fairbanks