UNIT 5: PROBALITY

Question 1

What does U mean when finding probability

*Context: interpret events P(AUB)

Answer 1

U= means “or”

Interpretation: the Probability of events A OR B occurring

Question 1

What does ⋂ mean when finding probability

*Context: Interprets events P(A⋂B)

Answer 1

⋂= means “and”

Interpretation: The probability of events A AND events B from occurring

Question 2

What does mutually exclusive mean?

Answer 2

Mutually exclusive events are events that can never occur at the same time

Question 3

Let A represent “being a high school graduate”, and let B represent “being a homeowner”

Are these two events mutually exclusive?

Answer 3

No, because they can happen at the same time; you can be a high school graduate and a home owner

Question 4

Interpret P (A | B)

Answer 4

Means the probability of A occurring, knowing (given) that B has occurred

means given

Question 5

Interpret P (B | A)

Answer 5

Means the probability of B occurring, knowing (given) that A has occurred

Question 6

What does it mean for two events to be independent

Answer 6

Two events are independent if the occurrence of one of them, DOES NOT, change the probability than the other will happen

Question 7

If two events are NOT mutally exclusive, then

Answer 7

the probability of event A or event B is the sum of the individual probabilities minus the probabilty of events A and B.

In other words, P(A U B) = P(A) + P(B) - P(A ∩ B).

Question 8

If two events are mutually exclusive, then

Answer 8

the probability of event A or event B is the sum of the individual probabilities.

In other words, P(A U B) = P(A) + P(B).

Question 9

What is the equation for P(AUB)

what if both events are mutually exclusive?

Answer 9

P(AUB)= P(A) + P(B)- P(A⋂B)

if both events are mutually exclusive: P(A⋂B) =0