Bayes' theorem
Probability theory · Mathematics
Study notes
Q: Using the bags example, given the drawn ball is red, find P(it came from Bag 1). P(Bag1|red) = P(Bag1)P(red|Bag1)/P(red). = (1/2)(3/5)/(2/5) = (3/10)/(4/10) = 3/4. The red ball probably (75%) came from Bag 1 - it has more reds!