[LONGITUDINAL]
input = {ka, V, k, a1}
EQUATION:
Cc = pkmodel(ka, V, k)
DEFINITION:
y1 = {distribution=lognormal, prediction=Cc, sd=a1}

[INDIVIDUAL]
input={ka_pop, omega_ka, V_pop, omega_V, k_pop, omega_k}
DEFINITION:
ka = {distribution=lognormal, prediction=ka_pop, sd=omega_ka}
V  = {distribution=lognormal, prediction=V_pop,  sd=omega_V}
k  = {distribution=lognormal, prediction=k_pop,  sd=omega_k}
