TI-83 Instructions
The Regression Line and the Correlation Coefficient
- Computing the Equation of the Regression Line and the Correlation Coefficient
- Enter the x values into List
L1.
- Enter the y values into List
L2.
- Press
STAT.
- Select the
CALC menu title.
- Select menu item #8,
LinReg(a + bx). (Menu item #4 is similar, but I prefer #8.)
- Press
ENTER. The phrase LinReg(a + bx) appears in the display.
- Press
2nd L1.
- Enter a comma.
- Press
2nd L2.
- Press
ENTER. The display shows the equation y=a+bx as a reminder of what a and b stand for. It also shows the values of a and b. Note that b is the slope b1 and a is the y-intercept b0.
- Below
a and b are displayed r2 and r.
- Graphing the Regression Line
- Follow the above steps to compute the equation of the regression line. A consequence of this is that the coefficients will be stored in the calculator. (This step is necessary.)
- Press
Y= (in the upper left corner).
- Select a function variable by moving the cursor to that line, say
Y1.
- Press
VARS. Some menu titles appear. The VARS menu title is highlighted
- Use the down arrow to select menu item #5,
Statistics...
- Press
ENTER. The Statistics menu titles appear.
- Select the
EQ menu title.
- Press
ENTER to select menu item #1, RegEQ. This is the expression a + bx that was previously calculated. It is now pasted into the function Y1.
- Create a scatter diagram. When the scatter diagram is drawn, the regression line will also be drawn.