2.1.884 Part 1 Section 18.104.22.168, BETAINV
a. The standard states that if probability < 0 or probability > 1, #NUM! is returned.
Office returns #NUM! if probability <= 0 or probability >= 1.
b. The standard does not place a restriction on the relationship between argument A and argument B.
Office returns #NUM! if argument A is greater than or equal to argument B.
c. The standard specifies that BETAINV uses an iterative search technique.
Office does not require an iterative search technique to be used.