Excel curve fits
Use these questions as a learning tool. Treat them like a quiz. Answer in your mind, and using the tool, and writing them down. Make it stick!
- Quiz yourself
- How much can you remember without this list (below)?
- What is missing from this list?
- Don’t just go through the posted notes to answer this. First, recall everything you can, and try it out. Then review notes to recall what you missed.
- Develop the “muscle memory” of using the tool
Trendlines
- Recall the process for creating a trendline on a plot
- Display the equation on the chart
- How to change the numeric formatting of the equation (e.g., to add more digits)
- Display the $R^2$ statistic
Nonstandard forms
- How to use a trendline to if your model equation is in a nonstandard form?
- That is, is not in the form of one of the trendline types?
- This is usually done to find parameters of a model fit
- Two methods:
- Massage the data to get it in that form. Group terms, take inverses, take logs, exponentiate…
- Write the function for the model in terms of parameters listed in cells. Then vary the parameters using the solver to minimize the sum square error between the data and the model.
R-squared statistic
- Obtain from a plot with a trendline
- Obtain using an explicit function
- What is the definition, and the geometric interpretation?