The initial step in the regression procedure is to select the two channels to regress, using the window shown at left.  The program won't let you attempt to regress a channel against itself, so you may have to do some fancy button-clicking to get your channels selected.

Next, you need to to chose the type of unit conversions.  Linear (least-squares), semi-log (log Y = a+b*X or Y = a+b*log X), and log-log (log Y = a + b*log X) regression models are available.  However, some of the conversions will not be available if the data range includes zero or negative values (since one can't take the log of a negative number)..

After the 'Continue...' button is clicked, LabAnalyst performs the calculations and produces a scatterplot of the data points in the block window (x values versus y values), along with the regression line.

• NOTE: regressing large data blocks can be time-consuming.   The program will post a warning message when it thinks calculation times will be lengthy.

The numerical results are the same as for the SLOPE vs TIME option described above -- except that only a single value of the intercept is shown.

You can test the slope against any user-defined value.  Enter the slope into the edit field and click the 'Test if p(slope) =' button (very low probability values are shown as "<.00001").

The 'Residuals' button will produce a scatterplot of residuals from the regression.   'Select New Channels' lets you set up a new regression of different variables.

You can use the 'Predict Values' button to use the regression equation to predict X from a given Y, or vice versa:

Some additional considerations:

• Note that in SLOPE and REGRESSION you cannot send results to disk or printer by hitting the 'p' key, as usual.  Instead, use the 'print' button (this button only appears if output has been selected from the FILE menu). 
• This option DOES NOT print to a tabular file (the output format is incompatible).