Logger Pro 3.10.1, released in September 2015, contains the new feature of weighted curve fits. This is an advanced feature, and is not needed for basic analysis.

To use this feature, create an additional column that will contain the direct weighting factor to be used. This column could be manually entered, or it could be a calculated column.

Create the standard Y vs X graph, and select the desired region.
Select Curve Fit from the Analyze menu.
Select the desired expression.
Using the weight column drop-down, select the column containing the weights.
Click Try Fit, and then OK if the fit is acceptable.

Direct weighting means that a point with a weight of 2 counts twice as heavily as a point with a weight of 1.

There are many ways to use weighted curve fitting.

-One is to force a fit to pass very close to a point; assign that point a large weight.

-A common method of weighting is to use the inverse square of the absolute uncertainty in a reading. Create with a column containing the uncertainties, and then define a calculated column that finds the inverse squares of the uncertainties. Use these values for the direct weighting.