Discrete Random Variables and Their Distributions Flashcards
(7 cards)
1
Q
What is a random variable
A
- A variable whose values are the outcomes of a random process
2
Q
What is the difference between discrete and continous random variables
A
- Discrete: Variables can take a finite or countable number of distinct values
- Continuous: Variables can take any value in an interval
3
Q
What is a probabilty distribution
A
- A function that assigns probabilities to each of the possible values of a random variable
4
Q
What are the two properites of a discrete probability distribution
A
- 0 <= p(y) <= 1 for all y
- The sum of p(y) = 1
5
Q
What is the mean of a discrete random variable called and how is it worked out
A
- The expected value, E(Y)
- Sum of y*p(y) from y to a predefined value
6
Q
How can E(cY) and E(aY+b) be written
A
- E(cY) = cE(Y)
- E(aY+b) = aE(Y) + b
7
Q
How is variance calculated
A
- V(Y) = E(Y^2) - E(Y)^2