The rules at the top of the decision table set forth the combination of conditions that may occur, and the action entries show what to do for each of them. For the illustration at hand, three conditions affect the data processing of each account: (1) an account balance less than $5, (2) an account balance less than $1,000, and (3) an account one year old or less. As defined, each of these conditions can now be answered ‘‘yes’’ or ‘‘no.’’ Figure 3-15 is a decision table for the illustration at hand, in which Y stands for ‘‘yes’’ and N stands for ‘‘no.’’ The combination of Ys and Ns in each column of the table illustrates each possible condition the system might encounter. Using Xs, the decision table also shows what course of action should be taken for each condition (i.e., how much interest should be paid to each account).