L1.05: Section 4
Section 4: Using Solver to choose the best kind of model
Sometimes data has a pattern for which more than one kind of model is a potential match. While visual inspection of the best-fit graphs will usually show which one is best, you can also choose between candidates by seeing which model type has the smallest best-fit standard deviation.Example 6: Does a quadratic model fit the population data better than the model in Example 3? Why?
Solution approach: [a] Use Solver with the Quadratic Model worksheet in Models.xls to fit the same data. [b] Add the computation of standard deviation to the worksheet. [c] Compare the standard deviation σ for the quadratic model with that of the exponential model.Answer: An exponential model is a better fit to this data than a quadratic model, because the best-fit exponential model has σ = 0.46 million, while the best-fit quadratic model has σ = 0.85 million, which is almost twice as large.