An abandoned search for a driving force

Given LeChatelier s Principle (when a stress is placed on a system at equilibrium, the system will adjust itself in such a way as to relieve the stress), it seemed that if 

the cyclical behavior is evident again. The integration process tends to smooth noise or variability in data and reveal more clearly the underlying trends in the data. The integral has the features of a sine wave with a period of slightly greater than 20 days. 

Investigation by the student revealed that the amounts reported to her for issues had been obtained for computer-generated checks only the total did not include checks that had been hand written. The clearings, however, were based on both computer-generated and hand-written checks. Thus, there was a simple explanation for the increasing integral. 

Although using the combined amounts of computer- and hand-written checks for modeling purposes would probably give more precise predictions, it turned out that it would be difficult to obtain the amounts for the hand-written checks on a timely basis. Thus, the modeling problem was redefined to predict the amount of money in checks that would clear the banks on a given day expressed as a function of the amount of money issued in computer-generated checks on previous days. 

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