# Math Help - Help with Expected Values

1. ## Help with Expected Values

A coin is thrown six times.
What is the expected total number of tails, given the last throw is a head.

Any ideas on how to do this?

2. ## Re: Help with Expected Values

you can do it with a tree diagram.

also since you have .5 chance of getting either tails or heads

it would be:

E(X) = 1/2 * ( 1++2+3+4+5+6) -----> since you have 6 trials

which is equals to = E(x) = 10.5

3. ## Re: Help with Expected Values

Originally Posted by hollymxox
you can do it with a tree diagram. also since you have .5 chance of getting either tails or heads
it would be: E(X) = 1/2 * ( 1++2+3+4+5+6) -----> since you have 6 trials
which is equals to = E(x) = 10.5
@hollymxox
If you are going to try to help, please at least understand the question.