12-22 Statistics
8312STAT.DOC TI-83 international English Bob Fedorisko Revised: 02/19/01 12:42 PM Printed: 02/19/01 1:37
PM Page 22 of 38
STAT CALC menu items 3 through C are regression models
(page 12.24). The automatic residual list and automatic
regression equation features apply to all regression
models. Diagnostics display mode applies to some
regression models.
When you execute a regression model, the automatic
residual list feature computes and stores the residuals to
the list name RESID. RESID becomes an item on the
LIST NAMES menu (Chapter 11).
The TI-83 uses the formula below to compute RESID list
elements. The next section describes the variable RegEQ.
RESID = Ylistname N RegEQ(Xlistname)
Each regression model has an optional argument, regequ, for
which you can specify a Y= variable such as Y1. Upon
execution, the regression equation is stored automatically to
the specified Y= variable and the Y= function is selected.
Regardless of whether you specify a Y= variable for regequ,
the regression equation always is stored to the TI-83
variable RegEQ, which is item 1 on the VARS Statistics EQ
secondary menu.
Note: For the regression equation, you can use the fixed-decimal
mode setting to control the number of digits stored after the decimal
point (Chapter 1). However, limiting the number of digits to a small
number could affect the accuracy of the fit.
Regression Model Features
Regression
Model Features
Automatic
Residual List
Automatic
Regression
Equation