Probability,Defectives and Mail Ordering

Probabilistic methods are applied to the problems facing the customer attempting to order items from a distributor where the probability of any item being faulty is a constant, q. The model involves only faulty items being returned by the customer in each round, and it is suggested that the situation being analysed is fairly general, conferming, for example, to that of the mail order customer exemplified by the record collector. Calculations are provided showing the extent of benefit from delaying purchase until a large order has accumulated.