Read each of the following cases. Explain for each case how you could select a sample having the best chance of being representative of the population using (1) unrestricted random selection and ( 2) systematic random selection ( refer to Appendix F. B).
a. You need to select a sample of recorded cash disbursements. The client used two bank accounts for general disbursements. Account 1 was used during January– August and issued checks numbered 3633– 6632. Account 2 was used during May– December and issued checks numbered 0001– 6000.
b. You need to select a sample of purchase orders. The client issued prenumbered purchase orders in the sequence 9000– 13999. You realize that if you select five- digit random numbers from a table and look for numbers in this sequence, 95 percent of the random numbers you scan will be discards because a table has 100,000 different five- digit random numbers. (The computer is down today!) How can you alter this sequence to reduce the number of instances in which the numbers in the table do not correspond to numbers in the population?
c. You need to select a sample of perpetual inventory records so you can count the quantities while the stock clerks take the physical inventory. The perpetual records have been printed in a control list showing location, item description, and quantity. You have a copy of the list. It is 75 pages long, with 50 lines to a page (40 lines on the last page). Find an efficient way to select 100 lines for your test of the client’s counting procedure.