Posted by Mandy on Wednesday, November 2, 2011 at 9:33pm.
If there are only two possible outcomes to an experiment then...
A.) the two corresponding probabilities must each be.50.
B.) the two corresponding probabilities could be any numbers between 0 and 1, but must add up to 1.
C.) the two corresponding probabilities could each be any numbers between 0 and 1.
D.) the two corresponding probabilities must be 0 and 1.

Stats  PsyDAG, Wednesday, November 2, 2011 at 9:37pm
The sum of all probabilities is always 1, B.