4.1 Probability Distribution

Question 1

Random Variable

Answer 1

Represents a numerical value associated with each outcome of a probability distribution.

Question 2

Discrete Random Variable

Answer 2

Has a finite or countable number of possible outcomes that can be listed.
EX: # of students, # of texts sent

Question 3

Continuous Random Variable

Answer 3

Has an infinite number of possible outcomes represented by an interval on a number line.
Ex: height, weight, age

Question 4

Discrete Probability Distribution

Answer 4

Lists each possible value the random variable can assume together with it’s probability.
conditions
1. Probability of each value is between 0 an 1 inclusive.
2. sum of all probabilities is one.

Question 5

Mean of a Discrete Random Variable

Answer 5

Represents the theoretical average of a probability experiment: does not give information on how outcomes vary.
Σ = sum of

Question 6

Expected value of a Discrete Random Variable

Answer 6

• equal to the mean of the random variable.
• plays a role in decision theory.
• can be negative.