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.