How to add the sigma value in model card

Hi all, 

I want to run a single TFT device with a model card and add the sigma on each parameter in the model card to check or generate different IdVd and IdVg.

May I know how to add the sigma to the TFT model card? Can I directly add the sigma in the model card such as "vth = -3.44133 +/- 30%". Thanks.

the model card as follows:

simulator lang=spectre

model ptft psitft
+type = p

+version = 2 tnom = 30
+tox = 1.4e-07 vto = -3.44133 vfb = -0.1
+von = 1.08412 dvt = 0 vkink = 731.172
+vsigma = 1.05631 vsigmat = 1 mu1 = 0.00601704
+mmu = 2.83143 mu0 = 78.3619 mk = 1.27054
+mus = 6.59718 rd = 4000 rs = 4000
+bt = 6.86572e-06 blk = 0.000623294 dd = 1.904e-07
+delta = 2.00001 dg = 2.41716e-07 eb = 0.633152
+eta = 9.47771 i0 = 0.455609 i00 = 142.134
+asat = 2.35988 at = 2.66359e-08 dasat = 0
+lasat = 2.88451e-05 lkink = 2.60148e-06 dvto = 0
+dmu1 = 0 capmod = 0 etac00 = 0.200962
+mc = 4.26265 rdx = 0 rsx = 0
+zeroc = 0 me = 2 mss = 1.5
+vmax = 34245.9 theta = 0 isubmod = 0
+lambda = 6.17405e-07 intdsnod = 0