Calculating sample sizes

Before sampling your data, you must calculate the statistically appropriate sample sizes and intervals.

To calculate sample sizes:

  1. Select Sampling > Calculate Sample Size.
  2. On the Main tab, select Monetary or Record.
  3. If you selected Monetary, enter the following information:
    1. In Confidence, enter the percentage of reliability you want the sample to generate. For example, a confidence of 95 indicates 95% reliability, or an error rate of 1 in 20.
    2. In 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.
    3. In Materiality, enter the maximum monetary amount that you are willing to accept without detection.
    4. In Expected Total Errors, enter the total monetary amount of errors expected in the population. This increases the sample size to allow for the expected errors.
  4. If you selected Record, enter the following information:
    1. In Confidence, enter the percentage of reliability you want the sample to generate. For example, a confidence of 95 indicates 95% reliability, or an error rate of 1 in 20.
    2. In Population, enter the total number of records in the table from which the sample will be drawn.
    3. In Upper Error Limit (%), enter the error rate you want to prove is not exceeded in the data set. This is the maximum amount of error that is acceptable in the data set without detection.
    4. In Expected Error Rate (%), enter the error rate expected in the population.
  5. Click Calculate.

    If you selected Monetary, the required sample size, interval, and maximum tolerable taintings are displayed in the Results panel.

    If you selected Record, the required sample size, interval, and number of tolerable errors are displayed in the Results panel.

  6. Click the Output tab.
  7. Select the appropriate output option in the To panel:
    • Screen – Select this option to display the results in the ACL display area. If the output table contains a large number of records, it is faster and more useful to save the results to a file than to display the results on the screen.

    • Print – Select this option to send the results to the default printer.

    • Graph – Select this option to create a graph of the results and display it in the ACL display area.

    • File – Select this option to save or append the results to a text file. The file is saved outside ACL.

    Note

    Output options that do not apply to a particular analytical operation are disabled.

  8. If you selected File as the output type, specify the following information in the As panel:
    • File TypeASCII Text File or Unicode Text file (depending on which edition of ACL you are using) is the only option. Saves the results to a new text file, or appends the results to an existing text file.

    • Name – Enter a file name in the Name text box. Or click Name and enter the file name, or select an existing file in the Save or Save File As dialog box to overwrite or append to the file. If ACL prefills a file 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 file in a location other than the project location. For example: C:\Results\Output.txt or Results\Output.txt.

    • Local – Disabled and selected. Saving the file locally is the only option.

  9. Click OK.
  10. If the overwrite prompt appears, select the appropriate option.
Related concepts
About calculating sample sizes


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