Random sampling selects a subset of rows from the data source. You can choose to sample by setting a percentage of rows from ...

Random sampling selects a subset of rows from the data source.  You can choose to sample by setting a percentage of rows from the source, or by setting a specific number of rows you want to be selected.  All rows from the data source have an equal probability of being selected.  The selected data will be placed in a new worksheet, and you can optionally place the unselected data into another worksheet.{0}
This method is typically used to reduce the amount of data used for mining, or to extract a fixed size sample from a large set of data.