random sampling

n. choosing a portion of a body of records for permanent retention through a statistical process that ensures each file within the series has an equal chance of being included in the retained set; statistical sampling choosing a portion of a body of records for permanent retention through a process that employs a pre-set pattern of selection to produce a sample of the whole; systematic random sampling Choosing a portion of a body of records for permanent retention through a process that ensures the retention of a statistical sample of each type or category of file within the series in the retained set at the same percentage as it was within the whole; stratified sampling or stratified random sampling