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.