Using the Student T distribution users can calculate the confidence interval as
Confidence Interval = X(mean) ± t (of (N-1)) ∗ (σ (of X)/√N)
However, the user would need to run 'N' simulations (with a different set of Random-Seeds for each run) to calculate the Mean (X) and the Standard Deviation (σ). NetSim GUI currently only supports execution of one sample per run.
Users can either run 'N' simulations using the GUI by changing the seed for each run (or) run any number of simulations automatically using a batch file or a python script. The seed values should be changed for each run. This automation can be done using NetSim's CLI mode.
The link https://www.dummies.com/education/math/statistics/using-the-t-distribution-to-calculate-confidence-intervals/ is a useful reference.