Discrete Random Variables Flashcards
(7 cards)
1
Q
What is a discrete random variable?
A
Variables that take a random, discrete value from a given numerical set
2
Q
How do we notate a probability distribution?
A
P(X=x)
3
Q
What is the total of all probabilities in a distribution?
A
1
4
Q
How to find the expected value of DRV? E(X)
A
Find the mean from the frequency table. Can be done in statistics mode or:
E(X)=Sigma((x)×P(X=x))
5
Q
How to find variance of DRV?
A
Put into statistics mode, use sigma². Or:
Var(X)=E(X²)-[E(X)]²
6
Q
What is E(X) affected by in scaling?
A
Addition/subtraction and multiplication/division
7
Q
What is Var(X) affected by in scaling?
A
Multiplication/division
