Quadratic Regression
The quadratic regression option finds the equation of a quadratic equation of
the form y = ax2 + bx + c that best fits a set of data.
First, press 
selecting option AEDIT to
enter the data .
The data shown here is the points {(2,11.4) (3,17) (5,27.3) (7,36.1) (11,47.7) (13,49.9)}
Press
DREG to view the regression options.
For quadratic regression, select opton 04Rg_x2
using 
followed by three
Press 
and select quadratic regression in the calculation screen.
Now press
followed by
.
Therefore, the best-fit quadratic equation for this data is approximately
y = -.23x2 + 7.13x - 2.11
The regression equation can be automatically stored in the equation editor
by entering the name of the equation, such as y1, after (L1,L2 as follows:
choose option A
and select y1 followed by
.
Note: The resulting quadratic equation is an exact fit if three non-collinear data points
are entered.
The Sharp does not calculate the correlation coefficient r, but it does calcularte
the coefficient of determination, r2.