Conditional probability
Probability theory · Mathematics
Study notes
Q: Roll a die. Given the outcome is even, find P(it is 6). B = even = {2,4,6}. The sample space shrinks to B! A = {6}. A intersect B = {6}. P(A|B) = (1/6)/(3/6) = 1/3. (Not 1/6 - the condition changed everything!)