I put them together, so that in each pair of country, one has twice the child mortality of the other. And this means that it's much bigger a difference than the uncertainty of the data.
我所选择的配对国家都是 一个的儿童死亡率是另一个的两倍,因为数据差距很大 因此数据本身的不确定性可以忽略不计