Logarithmic Regression


The logarithmic regression option finds the equation of a logarithmic equation of the form y = a + b ln x 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 logarithmic regression, select opton 07Rg_ln for base e using followed by six
or 08Rg_log for base 10 using eight



Press and select cubic regression in the calculation screen. Now press followed by .



Therefore, the best-fit logarithmic equations for this data are

y = -5.46 =21.52ln x and y = - 5.46 +49.61log x


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 Sharp calculates the correlation coefficient and the coefficient of determination, r2.