[LONGITUDINAL]
input = {ka, V, k, a, b}

EQUATION:
D=100
f1 = D/V*exp(-k*t)
f2 = D*ka/(V*(ka-k))*(exp(-k*t) - exp(-ka*t))
g1=a+b*f1

DEFINITION:
y1 = {distribution=normal,    prediction=f1, sd=a}
y2 = {distribution=logNormal, prediction=f2, sd=b}