# Discrete Random Variables

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• Created by: eleanor
• Created on: 11-04-15 14:54
• Discrete Random Variables
• is basically the outcomes of a probability experiment where the outcomes are discrete
• P(X = x) refers to the probability that X is equal to a particular x value
• the sum of all the probabilities must add up to one
• this can be used to find a constant or unknown in the probability
• E(x) is the expected values of x
• multiply x with the p(x) then add togehter
• varience= Var(x)
•
• E(aX+b) = aE(x) + b
• Var(aX + b) = a Var(X)
• Discrete Uniform data
• a discrete random variable X is defined over a set of n distrstinct values
• each value is equally likely
• E(X) = n+1/2
• Var(X) = (n+1)(n-1) / 12