Random Variable: Variable with a probability attributed to it
Regular Variable: Variable that is more intrinsic, like height
Discrete Variable: Variable where each possible value is a finite set or is an infinite set where each element is it's own distinct element, eg first element, second element etc.
Probability Mass Function (pmf): The pmf of a discrete rv is defined for every number x by p(x) = P(X=x)
Mass function criteria:
- All probabilities have to been between 0 and 1
- The total probabilities have to equal 1
Expected Value: The summation of the value and the probability of x over the entire set
Var?: Variance calculate the expected value but square the variable, then subtract the squared expected value
