Thought Provoking Questions:

Can STELLA be used to model AIDS growth?

STELLA MODEL:

Link here to see the STELLA models.

• Exponential growth model and
• Logistic growth model

YOUR STELLA MODELS:

You will build two STELLA models. First model the data for 1982 through 1990 with a proportional growth model. You can get an estimate for the growth factor by dividing the difference in population for consecutive years by the value of the population in the earlier year, repeat for several cases and average these values. Change this number if you need to to obtain closer results. Then, using all your data and the value you found for the constant asymptote, build a STELLA model which will simulate these actual values. Estimate a value for the growth rate and begin with your constant for the carrying capacity. Tweek these numbers until the result of your run mimics the actual values as well as possible. Save these values as you initial values and then add a slider bar to see what happens when one or the other number is changed. Show your teacher this model.