# Output tab (simulation)

The Output tab allows you to customize the output generated by the simulation.

Density Functions. Density functions are the primary means of probing the set of outcomes from your simulation.

• Probability Density Function. The probability density function displays the distribution of target values, allowing you to determine the probability that the target is within a given region. For targets with a fixed set outcomes--such as "poor service", "fair service", "good service" and "excellent service"--a bar chart is generated that displays the percentage of cases that fall in each category of the target.
• Cumulative Distribution Function. The cumulative distribution function displays the probability that the value of the target is less than or equal to a specified value.

Tornado Charts. Tornado charts are bar charts that display relationships between targets and simulated inputs using a variety of metrics.

• Correlation of target with input. This option creates a tornado chart of the correlation coefficients between a given target and each of its simulated inputs.
• Contribution to variance. This option creates a tornado chart that displays the contribution to the variance of a target from each of its simulated inputs, allowing you to assess the degree to which each input contributes to the overall uncertainty in the target.
• Sensitivity of target to change. This option creates a tornado chart that displays the effect on the target of modulating each simulated input by plus or minus one standard deviation of the distribution associated with the input.

Scatterplots of targets versus inputs. This option generates scatterplots of targets versus simulated inputs.

Box plots of target distributions. This option generates box plots of the target distributions.

Quartiles table. This option generates a table of the quartiles of the target distributions. The quartiles of a distribution are the 25th, 50th, and 75th percentiles of the distribution, and divide the observations into four groups of equal size.

Correlations and contingency table for inputs. This option displays a table of correlation coefficients between simulated inputs. A contingency table of associations between inputs with a categorical distribution is displayed when the simulation plan specifies generating categorical data from a contingency table.

Overlay results from separate targets. If the predictive model you are simulating contains multiple targets, you can specify whether results from separate targets are displayed on a single chart. This setting applies to charts for probability density functions, cumulative distribution functions and box plots. For example, if you select this option then the probability density functions for all targets will be displayed on a single chart.

Save the plan for this simulation. You can save any modifications to your simulation to a simulation plan file. Simulation plan files have the extension .splan. You can re-open the plan in the Run Simulation dialog or in the Simulation Builder. Simulation plans include all specifications except output settings.

Save the simulated data as a new data file. You can save simulated inputs, fixed inputs and predicted target values to an SPSS® Statistics data file, a new dataset in the current session, or an Excel file. Each case (or row) of the data file consists of the predicted values of the targets along with the simulated inputs and fixed inputs that generate the target values. When sensitivity analysis is specified, each iteration gives rise to a contiguous set of cases that are labeled with the iteration number.

If you require more customization of output than is available here, then consider running your simulation from the Simulation Builder. See the topic To run a simulation from a simulation plan for more information.