Assume that the current model has four model parameters.
XSPEC> error 1-4 ! Estimate the 90% confidence ranges for
each parameter.
XSPEC> error 9.0 ! Estimate the confidence range for parameters
1-4 with delta fit statistic = 9.0, equivalent
to the 3 sigma range.
XSPEC> error 2.706 1 3 1. 2 ! Estimate the 90% ranges for parameters 1
and 3, and the 1. sigma range for parameter 2.
XSPEC> error 4 ! Estimate the 1. sigma range for parameter 4.
XSPEC> error stop 20,,3 ! Estimate the 1-sigma range for parameter
3 after resetting the number of trials to 20.
Note that the tolerance field had to be included
(or at least skipped over).