Quiz #3 (Chapter 13 Vocab)

Question 1

Random Phenomenon

Answer 1

A phenomenon is random if we know what outcomes could happen, but not which particular values will happen

Question 2

Trial

Answer 2

A single attempt or realization of a random phenomenon

Question 3

Outcome

Answer 3

The outcome of a trial is the value measured, observed, or reported for an individual instance of that trial.

Question 4

Event

Answer 4

A collection of outcomes. Usually, we identify events so that we can attach probabilities
to them. We denote events with bold capital letters such as A, B, or C.

Question 5

Sample Space

Answer 5

The collection of all possible outcome values. The sample space has a probability of 1.

Question 6

Law of Large Numbers

Answer 6

The Law of Large Numbers states that the long-run relative frequency of repeated independent events gets closer and closer to the true relative frequency as the number of trials increases.

Question 7

Probability

Answer 7

The probability of an event is a number between 0 and 1 that reports the long-run frequency of that event’s occurrence. We write P(A) for the probability of the event A.

Question 8

Independence (informally)

Answer 8

Two events are independent if learning that one event occurs does not change the probability that the other event occurs.

Question 9

Theoretical Probability

Answer 9

When a probability is based on a model (such as equally likely outcomes), it is called a theoretical probability.

Question 10

Subjective Probability

Answer 10

When a probability represents someone’s personal degree of belief, it is called a subjective probability.

Question 11

Probability Assignment Rule

Answer 11

The probability of the entire sample must be 1. P(S) = 1

Question 12

Complement Rule

Answer 12

The Probability of an event occurring is 1 minus the probability that it doesn’t occur:
P(A^C) = 1 - P(A)

Question 13

Disjoint (Mutually Exclusive)

Answer 13

Two events are disjoint if they share no outcomes in common. If A and B are disjoint, then knowing that A occurs tells us that B cannot occur. Disjoint events are also called “mutually exclusive.”

Question 14

Addition Rule

Answer 14

If A and B are disjoint events, then the probability of A or B is P( A⋃B) = P(A) + P(B)

Question 15

Legitimate Probability Assignment

Answer 15

An assignment of probabilities to outcomes is legitimate if
- each probability is between 0 and 1(inclusive)
- the sum of probabilities is 1

Question 16

Multiplication Rule

Answer 16

If A and B are independent events, then the probability of A and B is
P(A∩B) = P(A) × P(B)

Question 17

Independence Assumption

Answer 17

We often require events to be independent (think about when this assumption is reasonable).