1. CH 23: Discrete random variables
B: Discrete probability distributions
A: Discrete random variables

2. 23A: random variables
Random variable – represents in number form the possible outcomes which could occur for some random experiment.
Discrete random variable X has a distinct number of possible outcomes
labeled: 𝒙 𝟏 , 𝒙 𝟐 , 𝒙 𝟑 , 𝒙 𝟒 , …, 𝒙 𝒏
to determine the number of discrete random variables we need to COUNT
Examples: # of new cars sold each year by Ford, # of As on the End of Semester test in AP Calculus, etc
Continuous random variable X could take possible values in some interval on the number line
to determine the number of discrete random variables we need to MEASURE
Examples: Heights of men which would all lie between 50<x<250cm, etc

3. 23A: Probability Distributions
For any random variable there is a corresponding probability distribution which describes the probability that the variable will take any particular value.
Notation:
Example:

4. 23B: Discrete probability distributions
CH 22: Probabilities may be assigned to events in a number of ways HOWEVER, if probabilities are assigned, the must satisfy the following rule:

5. 23B: Discrete probability distribution

6. 23B: Example

7. 23B: Last Example