Generating 2D Simulation Results

  To run the 2D Simulation tool:

  1. In Microsoft Excel with Crystal Ball loaded, open the workbook Toxic Waste Site.xls.

  2. In the Run, then Run Preferences, then Sampling dialog:

    • Set Random Number Generation to use the Same Sequence Of Random Numbers and An Initial Seed Value of 999.

    • Select Monte Carlo simulation.

      When using this tool, use these options to make the resulting simulations comparable.

  3. Select Run, then More Tools, then 2D Simulation. (In Microsoft Excel 2007 or later, select More Tools in the Tools group.)

    If this is the first time you have opened the 2D Simulation tool, the Welcome panel opens.

  4. If the Welcome panel opens, click Next.

    The Target Forecast panel opens.

  5. Be sure the Risk Assessment forecast is selected.

  6. Click Next.

    The Assumption Types panel opens.

  7. Move Body Weight and Volume Of Water Per Day to the Variability list.

    1. Select Body Weight.

    2. Press Ctrl and then click Volume Of Water Per Day.

    3. Click Move Right arrow .

      This separates the assumptions into the two types: Uncertainty and Variability.

  8. Click Next.

    The Options panel opens. The default number of trials for the outer (uncertainty) simulation is 50. The default for the inner (variability) simulation is the number of trials currently set on the Trials tab of the Run Preferences dialog.

  9. Set the following options.

    • Run outer (uncertainty) simulation for 100 trials

    • Run inner (variability) simulation for 1,000 trials

    • Show Only Target Forecast is selected.

      Use the default settings in the Report Options group.

  10. Click Run.

The simulations start. The tool first single-steps one trial to generate a new set of values for the uncertainty assumptions. Then it freezes these assumptions and runs a simulation for the variability assumptions in the inner loop.

The tool retrieves the Crystal Ball forecast information after each inner loop runs. The tool then resets the simulation and repeats the process until the outer loop has run for the specified number of simulations.