XSPEC> setplot rebin 3. 5 ! Bins are plotted that have at least 3 sigma,
or are grouped in sets of 5 bins.
XSPEC> setplot rebin 5 ! The significance is increased to 5 sigma.
XSPEC> setplot rebin,,10 ! The plotted bins can be grouped into up to
10 bins in reaching the 5 sigma significance
criterion.