He won about 25% because 6/12 would be 1/2 and 3 is 1/2 of 6 or a 1/4 so 25%
Hi, it will be really easy if you start out by plotting a tree diagram and tracing out the probabilities. Then you simply have to multiply the probabilities of placebo and improvement.
-----80% Medication -----76% improvement
-----24% no improvement
|
------20%Placebo --------62% no improvement
-----------38% improvement
Solving for P(placebo and improvement) = .20 x .38 = 0.076 = 7.6%
Divide 1 by 20.
1÷20= 0.05
so 1/20 written as a decimal is 0.05