3 Discrete random variables

With what we’ve got so far, we are able to answer questions like “what is the

probability of getting a heads?” or “what is the probability of getting 10 heads

in a row?”. However, we cannot answer questions like “what do we expect to

get on average?”. What does it even mean to take the average of a “heads” and

a “tail”?

To make some sense of this notion, we have to assign, to each outcome, a

number. For example, if let “heads” correspond to 1 and “tails” correspond to 0.

Then on average, we can expect to get 0

.

5. This is the idea of a random variable.