Education Technology

Solution 11919: Calculating Cubic Regressions on the TI-83 Plus Family of Graphing Calculators.

How do I calculate a cubic regression on the TI-83 Plus family of graphing calculators?

The example below will demonstrate how to calculate a cubic regression.

Example: Find the cubic regression equation for the x and y values below.
xStat: {80, 84, 86, 91, 93, 96}
yStat: {10, 7, 9, 18, 19, 15}

Please Note: If you have data in L1 and L2 or encounter an error please follow the steps below:
1) Press [stat] [5] [enter] to restore default lists
2) Press [stat] [4] [2nd] [1] [,] [2nd] [2] to delete the data in all L1 and L2

To enter the data:
1) Press [stat] [1] to access the STAT list editor
2) Enter data in L1 by pressing 80 [enter] 84 [enter] 86 [enter] 91 [enter] 93 [enter] 96 [enter] 
3) Enter data in L2 by pressing [→] then 10 [enter] 7 [enter] 9 [enter] 18 [enter] 19 [enter] 15 [enter]
4) Press [2nd] [mode] to return to the home screen.

To calculate the cubic Regression (ax3+bx2+cx+d):
5) Press [stat] then [→] to select the CALC menu
6) Press [6] to select 6:CubicReg.
4) Press [2nd] [1] [ , ] [2nd] [2] to specify which lists to use for the regression
5) Press [ENTER] to perform the regression calculation.

The calculator will display the form of the equation (y=ax3+bx2+cx+d) and then list the values for the coefficients.

Please see the TI-83 Plus Family guidebooks for additional information.

Last updated: 7/27/2023