where is the aggregate between-group variance component, is the aggregate within-group component, is the GDP share of group , is the GDP-share associated with city in group , denotes average level of the groups, finally is the average of cities in group . In the light of their locations, the 30 provincial capital cities involved was grouped into 3 categories with regard to the three Chinese economy-zones established in the Seventh Five-Year Plan and commonly used in China, i.e., East, Middle, and West. ) (I T B ) (I T W i y i ij y j i I i i I i