Discrete Random Variables

Question 1

What do probabilities add up to in discrete random variables

Answer 1

1

Question 2

What is the mean for discrete random variables

Answer 2

Sum of x times P(X=x)

Formula sheet

Question 3

What is the formula for E(X^2)

Answer 3

Sum of x^2 times P(X=x)

Question 4

What is the equation for variance of discrete random variables

Answer 4

E(X^2) - [E(x)]^2

Or standard deviation squared

Question 5

What is the mean affected by in discrete random variables and what is the equation

Answer 5

+ - x %

E(aX + b) = aE(X) + b

Question 6

What is the variance affected by in discrete random variables and what’s the equation

Answer 6

x and %

Var(aX + b) = a^2 Var(X)