Laspeyres index formula

Laspeyres index formula　拉斯佩尔指数公式　

An index calculated with a Laspeyres index formula measures price Laspeyres Index changes in relation to the base period’s market basket and thereby“fixes”formula the market basket by holding the items in it constant.It calculates what that market basket would cost in later periods，even if some of the items were no longer purchased.For our hypothetical shopper，the Laspeyres index formula uses what she purchased in the first week as the base of the calculation——the fixed market basket.All comparisons are made with respect to the quantities of items she purchased and the prices she paid for them in the first week.