Discrete Descriptive Statistics - Yousef's Notes
Discrete Descriptive Statistics

Discrete Descriptive Statistics

#Expectation

The expectation or mean of a random variable X dented as E(X) is defined as

$$ E(X) = \sum_{x \in X} xp(x) $$

The expectation can be interpreted as the mean value of a large number of observations from the random variable X.

#Variance

$$ V(X) = E((X - E(X))^2) = E(X^2)-E(X)^2 = \sum_{x \in X} (x - E(X))^2 p(x) $$