Topic 4

Question 1

What is an...
Event
Union
Intersection
Complementary Event

Answer 1

Event - set of possible outcomes from experiment

Union - A u B - A and B both can happen

Intersection A n B - A and B have to happen

Complementary event - A’ - A doesn’t happen

Question 2

P (X u Y) =

Answer 2

P(X) + P(Y) - P(X n Y)

Question 3

What is the condition probability and the general rule

Answer 3

Conditional probability of event A occurring given that event B has already occurred written as P(A|B)

P(A|B) = P(A n B) / P(B)

Question 4

Relations between events
State meaning of...
Independent 
Mutually Exclusive
Exhaustive

Answer 4

Independent - if the outcome of A doesn’t affect outcome of B - written as
P(A|B) = P(A)

Mutually Exclusive - Two events cannot occur at the same time
P(A u B) = P(A) + P(B)

Exhaustive - covers all possible outcomes