Linear Regression Line (Line of Best Fit)—calculate
STAT/CALC/8:LinReg(a+bx).
LinReg(a+bx)
ENTER
key, choose the Xlist
and Ylist
. Since the Year data is in L1 and the Time data is in L2, enter L1,L2 after LinReg(a+bx). The comma (,) button is just above the 7 button.LinReg(a+bx) L1,L2
, press ENTER
.You should now see:
The regression line is given as:
where a is the Y intercept of the regression line and b is the slope of the regression line.
Now let's plot this line on the scatterplot.
Linear Regression Line (Line of Best Fit)—plot on scatterplot
The TI calculator stores the last regression line that you calculated until you calculate another one.
Y=
a
and b
: VARS/5:Statistics.
EQ
(right arrow twice).2:a
+
button.VARS/5:Statistics
.EQ
(right arrow twice).3:b
X, T, Θ, n
button.You should see:
Note: As long as you don't change Y1
, each time you find another regression line, a and b will automatically be saved with the new values and the new line will be graphed.
You can toggle Y1
on and off. When the "=" is highlighted, the graph is ON. To turn it OFF, use the left arrow to highlight the "=," then press ENTER
. Repeat to turn the graph back on.
If you've set up the scatterplot and set up Y1=
, you can ZOOM/9:ZoomStat
to see the regression line plotted on the scatterplot.
You should see a graph window with the scatterplot and the regression plotted on it. Choose TRACE
and then use the up and down arrows to toggle between the line of best fit and the scatterplot. Use the left and right arrows to see each individual data pair on the scatterplot.