DVD在线租赁的需求预测模型

Demand Forecast Model of DVD On Line Tenancy

根据CUMCM-2005 B题已有的问卷调查,来确定购买每种DVD的数量。假设DVD1的需求数量和被租赁出去的DVD在1个月内的归还数量都是随机变量,满足正态分布,由此建立了概率模型,并得出结论是需要准备6 355张DVD1,才能在90%的概率意义上,保证愿意观看该DVD的会员至少50%在1个月内能够看到该DVD。准备的DVD1的数量的微小变化对目标影响不大,不过最好不要低于6 000张,也不必超过6 500张。而需要4 230张DVD1,才能保证在3个月内至少95%的会员能够看到该DVD。

In this paper, the first problem of CUMCM -2005B has been studied, which is to find how many DVDs to purchase according to the questionnaires. This paper supposes the demand of DVD is a random wariable and obeys normal distribution, and so is the number of DVDs which are returned in a month. Then this paper sets up a probability model and draws a conclusion that 6 355 DVD1 s need to be purchased so as to satisfy the problem＇s objective to the 90% probability meaning. There is a little influence on the objective from a little change in the number of purchasing DVD1, which had better range from 6 000 to 6 500. It needs 4 230 DVDls to assure that 95% members who like DVD1 can watch it in 3 months.