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 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 = -1.61 + 3.76 ln x.


Note: The TI-92 calculates the correlation coefficient, r and the correlation of determination, R2.