Sampling monetary unit records

You can create a new table that contains a representative sample of the monetary data in the active table.

Note

This procedure does not include filtering (IF statements) or scope parameters because applying these options compromises the validity of the sample.

To sample monetary unit records:

  1. Select Sampling > Sample Records.
  2. On the Main tab, in the Sample Type panel, select MUS.
  3. Do one of the following:
    • Select the field to sample from the Sample On drop-down list.

    • Click Sample On to select the field, or to create an expression.

  4. In the Sample Parameters panel, specify a sample selection method:
    • Fixed Interval – Items are chosen based on a random start number and intervals that you specify.

    • Cell – The data set is broken into groups that equal the size of the specified interval. One random item is chosen, based on a seed value that you specify, from each group. Cell sampling is also called random interval sampling.

    • Random – Items are randomly chosen based on a seed value that you specify.

  5. Depending on which sample selection method you are using, enter three of the following required values:
    • Interval – Enter the interval value that was generated by calculating the sample size.

      Note

      If you are using fixed interval sampling and have not already calculated the sample size, you can click Size to open the Size dialog box.

    • Start – Enter a random start number that is greater than zero and less than the interval value.

    • Cutoff – Enter an optional cutoff value.

      Records with monetary units above this value are included in the top stratum and therefore automatically selected for the sample. If you leave this field blank, the default cutoff value is the interval generated by calculating the sample size. If you enter a cutoff value greater than the interval value, none of the items will fall in the top stratum.

    • Seed – Enter any random number. This number will be used to randomly select a record from within the interval. If you enter zero, ACL will generate a random seed.

    • Size – Enter the number of selections specified when you calculated the sample size.

    • Population – Enter the absolute value of the field that will be sampled. That is, the combined total of all values in the field, with negative values calculated as positive values.

  6. Do one of the following:
    • In the To text box, specify the name of the ACL table that will contain the output results.

    • Click To and specify the ACL table name, or select an existing table in the Save or Save File As dialog box to overwrite or append to the table.

    If ACL prefills a table name, you can accept the prefilled name, or change it.

    You can also specify an absolute or relative file path, or navigate to a different folder, to save or append the table in a location other than the project location. For example: C:\Results\Output.fil or Results\Output.fil. Regardless of where you save or append the table, it is added to the open project if it is not already in the project.

  7. If you are connected to a server table, do one of the following:
    • Select Local to save the output table to the same location as the project, or to specify a path or navigate to a different local folder.

    • Leave Local deselected to save the output table to the Prefix folder on the ACL Server.

      Note

      For output results produced from analysis or processing of ACL Analytics Exchange server tables, select Local. You cannot use the Local setting to import results tables to ACL Analytics Exchange Server.

  8. Select or deselect Use Output Table depending on whether or not you want the ACL table containing the output results to open automatically upon completion of the operation.
  9. Click the More tab.
  10. In the Output panel, select one of the following:
    • Record – The entire record will be contained in the output results.

    • Fields – Only the selected fields will be contained in the output results.

  11. If you chose Fields in the Output panel, do one of the following:
    • Select the field(s) to extract from the Extract Fields list.

    • Click Extract Fields to select the field(s), or to create an expression.

  12. Select one or more of the following options:
    Note

    Subsample is available only if Fields output is selected. Report Selection Order is available only if both random sampling and Fields output are selected.

    • Subsample – When Subsample is selected, an additional field called SUBSAMPLE is included in the output results. This field contains the specific random monetary unit used to select that item.

      Note

      Top stratum cutoff items contain a 0 (zero) value in the SUBSAMPLE field because they are automatically included in the sample and no selection value is assigned to them.

    • Report Selection Order – Select this option to include an additional field called ORDER in the output results. This field contains the order number that the particular item was selected in.

    • No Repeats – Select this option to omit items that have already been selected for the sample.

      Note

      Omitted items are not replaced. You should consider oversampling the data set to compensate for non-replacement.

  13. If you want to append the output results to the end of an existing ACL table, do one of the following:
    • Select Append To Existing File if you are certain the output results and the existing table are identical in structure.

    • Leave Append To Existing File deselected if you want ACL to compare the record lengths of the output results and the existing table. If the record lengths are not identical, the data structure is not identical.

    Note

    Leaving Append To Existing File deselected is recommended if you are uncertain about the data structure. For more information about appending and data structure, see Appending results to ACL tables and text files.

  14. Click OK.
  15. If the overwrite prompt appears, select the appropriate option.

    If you are expecting the Append option to appear and it does not, click No to cancel the operation and see Appending results to ACL tables and text files.

Related concepts
Saving results and specifying results output folders
About sampling types
About sample selection methods
About conditional sampling
Monetary unit sampling options


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