AP Statistics Audio Lectures
Random Variables
by Arnold Kling

To hear the lecture, click here.

"Random Variable" is a mathematical representation of a random process. Analogous to a circle or a triangle geometry

Random variables assign numbers and probabilities to outcomes of random processes; examples:

Random Variables can be Continuous

think of X as the midpoint of a range, and p(X) as the probability that the random variable will fall within that range

Random Variable Represented as a Histogram

Random Variable and Gambling

A lottery that costs $1, has 10,000 entrants, a grand prize of $5000 and four smaller prizes of $100 each

+ $49991/10,000
+ $994/10,000
- $19,995/10,000

Many mathematical models of random variables (many shapes in geometry)

Two used in this course: binomial; normal (bell curve)

Two others mentioned briefly: geometric; uniform (rectangular)


Random variables are mathematical representations of random processes.

We assign a number to each outcome and associate a probability with that number.