A company wishes to give an estimate of the total amount of accounts receivable owed by its customers. These customers, along with the amount they owe, are listed alphabetically in a 5001 pages ledger. Each page has 40 different names, with the exception of the last, which has only 3, and which is therefore excluded from the sampling frame; therefore, we consider that there are only N = 200,000 customers. We use a cluster sampling to give an estimate of the total amount of accounts receivable, a cluster being defined as a pair of pages facing each other. Thus, each cluster contains 80 names. An EAS of ten clusters was randomly selected, and the average amount owed (in dollars) for the 80 clients in each cluster was determined. Give a 95% C.I. for the average and for the total amount owed by customers for the following sample :