User's Manual Part 2
Nomad User’s Manual Appendix C – Confidence Interval Calculation
Copyright © Spirent Communications, Inc. 2013 148
Appendix C – Confidence Interval Calculation
The Nomad Call Performance output reports employ a 90% Confidence Interval for call initiation
failure and dropped call events. The Confidence Interval allows us to report, with 90% confidence,
that the event rate for a given device will fall within the calculated range above and below the
measured value. The Confidence Interval is calculated as a function of the estimated standard
deviation of the sample proportion (% dropped calls or % call initiation failures) and the standard
normal distribution function.
therefore