Probstat/week2 practice 1 solutions

This are solutions to Probstat/week2 practice 1.

Conditional probability review

1.1 There are 7 numbers divisible by 2 and 3 (0, 6, 12, 18, 24, 30, 36). There are 14 numbers divisible by 3. Let A be the event that a random number is divisible by 3. Let B be the event that a random number is divisible by 2. We want to compute P(B|A), which is P(AB)/P(A) = 7/14 = 1/2.