Examples:

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).