SOLUTION: How to find E(x^2) in Probability distribution

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Question 752187: How to find E(x^2) in Probability distribution
Answer by reviewermath(1029) About Me  (Show Source):
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Q: How to find E(X^2) in Probability distribution
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A: If you know the mean and variance of the random variable X, then use
the equation Var(X) = E%28X%5E2%29+-+%28E%28X%29%29%5E2 to solve for E%28X%5E2%29.
If you don't know the mean and variance, then use the following formulas:
1. If X is a continuous random variable then E%28X%5E2%29 = int%28+%28x%5E2%29f%28x%29%2C+dx%2C+-infinity%2C+infinity+%29 where f(x) represents the probability distribution function of X.
2. If X is a discrete random variable then E%28X%5E2%29 = sum%28%28x%5E2%29p%28x%29%29, for all values of x, where p(x) represents the probability mass function of X.