This chart illustrates the principle underlying setting the alarm threshold.
The risk of errors in the operators' perception of the alarm should be minimal.
The risk of alarm errors is the sum of the risks of alpha and beta errors.
Risk = predicted costs * rate estimate of the error.
Rate estimation is based on measurements in the history of operation
Predicted costs is based on estimates by the systems (or safety) engineers.
Updated on 15 Mar 2017.