# How do you calculate expected value?

Nov 15, 2015

Same thing as the mean

#### Explanation:

Expected value is another way of stating the mean. It can be calculated one of two ways:

For a set of numbers, take the sum divided by the number of data points. So 4,6,11: (4+6+11)/3 = 21/3 = 7

If it's a probability distribution then it's the sum of probabilities times each possible outcome

X=1 with probability 0.5
X=2 with probability 0.2
X=3 with probability 0.3

Mean = 1(.5) + 2(.2) + 3(.3) = .5 + .4 + .9 = 1.8