Stratified

For a stratified sample, specify the following:

• Column: Select the column for stratification.

• Seed: Default seed=12345
  You can specify a different integer.

• Case ID (optional): Select a case ID from the drop-down list.

  If you specify a seed and a case ID, the sample is reproducible.

• Distribution: Specify how the sample is to be created. There are three options:

  • Original: The distribution of the selected column in the sample is the same as the distribution in data source.
    For example, if the column GENDER has M as the value for 95 percent of the cases, then in the sample, the value of GENDER is M for 95% of the cases.

  • Balanced: The distribution of the values of the column is equal in the sample, regardless of the distribution in the data source.
    If the column is GENDER, and GENDER has two values M and F, then 50% of the time the value of GENDER is M.

  • Custom: You define how the values of the columns are distributed in the sample. You must run the node once before you define the custom distribution. Click Edit to open the Custom Balance dialog box.

The Stratified dialog box displays a histogram of the values of the selected column at the bottom of the window.
To see more details, click View to display the Custom Balance dialog box.