There are three options for combining the values that are found for a
specific choice.  The values can be  combined as a simple average of the
values.  The values can be combined as dependent probabilities, with the
values multiplied as fractions. The third option is to combine the values
as independent probabilities. (i.e. (1 - ((1-value1) * (1-value2))))

ONLY the average mode can be used if negative confidence values are used.

The user will have the option of changing the option chosen when they run
the knowledge base.
