Section 2.4

Question 1

the probability of A given B has happened:

Answer 1

𝑃(𝐴 ∩ 𝐵)
𝑃(𝐴)

Question 2

p(event):

Answer 2

number outcomes in event
number outcomes in sample space

Question 3

and” is intersection of events ”∩” which essentially leads to “multiplying” probabilities

Answer 3

o Multiplicative rule for general events: P(A and B) = P(A) P(B|A)
o Multiplicative rule for independent events: P(A and B) = P(A) P(B) as P(B|A) = P(B)