Data Set Explained:
A simple example of a data set is your bank account details. For simplicity, it comprises of (1) sequence number, (2) date, (3) transaction description, (4) debit, (5) credit and (6) balance.
For this illustration, I've listed 6 fields. And, of the 6 fields, account balance is a field that uses simple calculations. That's because, the transactions on its own don't show balances. Hence, we need to use a simple sum (or deduction) to identify these balances.