Education Technology

# Knowledge Base

## Solution 11810: Calculating a Cubic Regression on the TI-89 Family, TI-92 Family and Voyage™ 200 Graphing Calculators.

### How do I calculate the cubic regression on the TI-89 Family, TI-92 Plus and Voyage 200?

The TI-89 family, TI-92 family, and Voyage 200 allows calculating cubic polynomial regressions for a given set of data. Please refer to the example below.

Data for this example:

x values: 0,1,2,3
y values: 0,2,3,4

Solution:

1) Press [APPS][6][3] (If the Apps Desktop is on, press [APPS], select Data/Matrix Editor, and press [3]).
2) Press the down arrow twice.
3) In the box beside Variable: type a variable name using the alpha characters (e.g. TEST).
4) Press [ENTER][ENTER].
5) Enter the x values under c1 and press [0][ENTER][1][ENTER] etc.
6) Enter the y values under c2 and press [0][ENTER][2][ENTER] etc.

7) Press [F5], then the right arrow, then [3] [ENTER].
8) Press the down arrow, then press [C][1] (Indicates the x variables are in c1). On the TI-89 family, press [C][ALPHA][1].
9) Press the down arrow, then press [C][2] (Indicates the y variables are in c2). On the TI-89 family, press [ALPHA][C][2].
10) To graph the line, select an equation number after Store RegEQ to...

11) Press [ENTER][ENTER].

A dialog box will display the cubic regression variables.

12) Press [♦][F3] on the TI-89 family, [♦][R] on the TI-92 family and Voyage 200.

Please see the TI-89 family, TI-92 family, and Voyage 200 guidebooks for additional information.