A+ » VCE » Maths Methods U3 & 4 Master Notes » A4 Probability and Statistics » 2.2 Expected Value (Mean)

# 2.2 Expected Value (Mean)

#### Expected Value (Mean)

• You already know what an average is. Expected value is similar in this sense (after all, it is known as mean too).
• Since random variables have a list or range of possible outcomes with probabilities associated, we can determine the mean of the random variable, known as its expected value.
• The formula for expected value is given by

E(X)=\sum_{x} x \cdot \operatorname{Pr}(X=x)=\sum_{x} x \cdot p(x)

where E(X) represents the expected value of X.

• E(X) can also be denoted as the Greek letter \mu (mu), which means the mean of X.
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