Selection proportional to size

This procedure is used to draw a random sample from a list of primary sampling units where the probability of sampling is proportional to the number of secondary sampling units within each primary unit. The data to be used is introduced into the program via a two column comma separated value (*.csv) file. The first column provides the identifier of the primary sampling unit. The identifier column is a text field, therefore any kind of character may be used (number, character, or a combination of numbers and characters). The second column provides the number of secondary sampling units present within each primary sampling unit.

Enter the number of primary samples you wish to draw from the list and click RUN. A random sample of primary units will be drawn from the list. This function returns the total number of primary units, the total number of secondary units, the number of primary units to be sampled, the identifiers of the primary units, and the number of times each primary unit should be sampled.