#1
I cannot figure this question out for the life of me :(

A game consists of tossing two coins, first a dime and then a nickel. For each coin which comes up a head you win the value of the coin. For each coin which comes up a tail you get nothing.

I have gotten this so far - that the outcomes would be {HH,HT,TH,TT} - each outcome with probability .25 - winnings are 15,10,5,0

a) Find the mean or expected winnings

b) Find the standard deviation of your winnings.

c) If you had to pay a dime to play the game, what would be the mean of your winnings?

d) If you had to pay a dime to play the game, what would be the standard deviation of your winnings?