Creating models for sets of data is a key skill for the businessperson, scientist, politician, or anyone else who uses data to make decisions. This is because modeling enables one to make predictions. The graphing calculator can help with this task. Given a set of data, one can create a model that is a linear, quadratic, cubic, quartic, exponential, logarithmic, sinusoidal, logistical, or power function. Determining which model is the most appropriate model is addressed in statistics courses, although a fundamental rule of thumb has to do with the plot of the residuals of the regression.
This appendix shows how to use the two most popular graphing calculators—the TI 8xx series (83+, 84, and 84+) and the TI Nspire—in working through three problems: a linear regression based on data obtained from a group of students reading a tongue twister, a quadratic regression based on the heights of a bouncing ball measured with a motion detector, and an exponential regression using the maximum heights to which the ball bounces. The keystrokes and screen shots are given so that you can use the tool.