The index works by taking a weighted average of the price of imported iron and domestically produced iron ore to produce a composite number.
这种指数通过对进口铁和国产铁矿石取以加权平均价格以此产生一个合成数。
2
Moreover, the ratio between the number of records and the number of index keys indicates, on average, the number of RIDs associated with each index key.
而且，记录的数量与索引键之间的比例说明，通常，RID 的数量与每个索引键都有关联。
3
The structure of the index tree decides the averageindexnumber to be visited, but even regarding the same index structure, the average visit time is different if the broadcast sequence is different.