Sampling is the method of studying from a few selected items, instead of the entire big number unit. The small selection is called a sample.
Sampling is used in auditing to enable the auditor to take a few items from transactions so that he can study them and project the conclusion to the entire population. Sampling is useful because it reduces the time of performing the task also it saves money which would be required to perform tests or tasks on the entire population. The large the sample the more the conclusion of sampling near that of the entire population.