The general growth model, is similar to the example that we previously considered:

y = b0 + b1*exp(b2*x) + error

This model is commonly used in studies of any kind of growth (y), when the rate of growth at any given point in time (x) is proportional to the amount of growth remaining. The parameter b0 in this model represents the maximum growth value. A typical example where this model would be adequate is when one wants to describe the concentration of a substance (e.g., in water) as a function of elapsed time.