Uncertainties in Tables & Plots

Uncertainties listed in all tables and output files of the ThermoData Engine (TDE) software represent estimates of the Combined Expanded Uncertainty with 95% Level of Confidence for the property value. Definitions of terms are provided here.

In the following table, the term Uncertainty is equivalent to Combined Expanded Uncertainty (with 95% Level of Confidence).

Uncertainties available in the Navigation Tree:

• Experimental Data: Preliminary uncertainties are estimated at NIST/TRC for each experimental data point in the database of experimental values incorporated in the TDE software. These values are listed in all tables listing experimental data from primary sources.
• Predicted Data: Uncertainties are estimated within the TDE software for all predicted property values.
  NOTE: Predicted values should not be confused with Evaluated Data, which are the critically evaluated properties generated dynamically by the TDE software. See the Glossary of Terms in TDE for definitions.
• DEFAULT REPRESENTATIONS: Uncertainties for experimental and predicted data are the same as above. Evaluated data (i.e., values generated by TDE are shown in graphical form (blue lines) only, and no uncertainties for the evaluated data are shown or listed in this section of the Navigation Tree.
• EVALUATED DATA: All uncertainties listed and shown are those estimated as part of the dynamic critical evaluation completed by the TDE software. This is the only section of the Navigation Tree in which uncertainties are given for the values critically evaluated by the TDE software.
  NOTE: Evaluated Data should not be confused with Predicted Data. See the Glossary of Terms in TDE for definitions.
• ALTERNATIVE EQUATIONS: Uncertainties in tables and plots in this section of the Navigation Tree are those for the experimental and predicted data only. These values are identical to those given in the Experimental and Predicted Data and Default Representations sections of the Navigation Tree.