[Limdep Nlogit List] What is mean by non-significant value of tau in Zero inflated model?

[Bhubaneswor.Dhakal at scionresearch.com]

Dear Green

Could you please advise me the following queries?
1. What is mean by non-significant value  of tau in zero inflated model.  I
read LIMDEP manual version 9 (pp. E25-46) but could not understand.
2. How can we do sensitivity analysis of travel cost variable? I am
requesting about travel cost analysis method that people advise to do a
sensitivity analysis to account  appropriate percentage of travel  time
cost in travel cost variable.

Thank you.
Best regards

B.Dhakal