Discrete Random Variables Flashcards
1
Q
What is the formula for the mean of a discrete random variable?
A
Sigma(xipi)
2
Q
What is the formula for variance?
A
Sigma(xi2pi) - Sigma(xipi)2
3
Q
How do operations affect expectation?
A
E(aX + b) = aE(X) + b
4
Q
How do operations affect variance?
A
Var(aX + b) = a2Var(X)
5
Q
How can the expectations of two random variables be combined?
A
E(X1+ X2) = E(X1) + E(X2)
E(X1- X2) = E(X1) - E(X2)
6
Q
How can the variance of two random variables be combined?
A
Var(X1+ X2) = Var(X1) + Var(X2)
Var(X1- X2) = Var(X1) + Var(X2)
7
Q
What is the formula for the mean in discrete uniform distribution?
A
1/2(n+1)
8
Q
What is the formula for the variance in discrete uniform distribution?
A
1/12(n2-1)