Lognormal in Vensim

[tomfid]

Not at all dumb/boring.

I can think of two ways to do a Monte Carlo with a lognormal distribution.

Assuming your equation is:
z = EXP( mean_ln_x + RANDOM NORMAL( -6,6,0,stdev_ln_x,seed ))

1.
You can make the seed parameter a VECTOR input in the sensitivity setup. Or, use a seed of 0 and vary the NOISE SEED. https://www.vensim.com/documentation/in ... e_seed.htm

2.
Separate z back into its components:
z = EXP( mean_ln_x + normal_variation)
normal_variation = NORMAL( -6,6,0,stdev_ln_x,seed ) {i.e. set this in your sensitivity setup}