The rate of growth in per capita income is by far the most important single variable in determining whether children will be better off than their parents.
到目前为止，人均收入的增长率是决定子女比父母富裕的最重要的单一变量。
2
Single age variable stock volume growth model had low coefficient of determination, but it was improved a lot by introducing site index and stand density index in reparameterization.