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 to enter the data .

Press to view the statistics calculation options.

The values of x must be greater than zero. (This is because the method for determining the values of a and b in the regression equation is a least-squares fit on the values for ln x and y.) Press .

Enter the columns to be used for the x and y entries, c1 and c2 in this case.

The regression equation can be automatically stored in the equation editor by selecting the Stor RegEQ

Therefore, the best-fit logarithmic equation for this data is approximately y = 2.84 + 3.06 ln x.