Steps for
generating logarithmic (or other) regression models.

1.) Insert Chart, choose scatter point type.

2.) Enter data matrix, top row x value (Rf), bottom row y value (bp) (one can
choose whether rows or columns are used for data series.

3.) Finish chart, add trend-line. Logarithmic or exponential can appear as
straight lines on log paper.

4.) Right click, format trend-line, options, show equation. (Log regression
model should appear in the form y = a Lnx + b where a and b are constants.)

5.) Plug values into equation by hand or typing equation into spreadsheet and
cutting and pasting.

(The scatter point model is used as a means of generating this regression line
because as of now I know of no way to independently enter x values in the log
graph option. I generally just use my graphing calculator although the method
presented here will work as well. If anyone knows how to enter two coordinate
data points into log graphs on excel (not just change the name of the x values)
please let me know. The problem is that the program assigns arbitrary values
that are evenly spaced as x values for an entered data series, thus if your
actual x values are not evenly spaced, the regression model will be
inaccurate.)