elementary coin game problem

[Phil]

Fair coin

You can play a game

Keep flipping the coin

until you get "tails"

Number of "heads" that you saw is how much $$$ you win

E.g.

if you got "heads" "heads" "heads" "tails" you win $3.00

What's the expected value of this game

[carrot]

Isn't that the negative binomial distribution? I don't remember the expected value, though. I think it was something like 1/p? If so, then 1/.5 give you an expected value of $2.

[3rookie]

1

[Da Bears!]

Sounds geometric to me.....$1

[Dr T Non-Fan]

What's wiki's solution? I think we could discuss this for 400 posts or so.

[Da Bears!]

Originally Posted by mlschop

negative binomial expected value is r times Beta. this is geometric since you are looking for first loss, so r = 1. Isn't Beta probability of success, so it's 0.5, so wouldn't the E[X] = 0.5?

where is everyone getting 1?

If you succeed on the first attempt, you continue for another attempt. So.....E[X] = 1/2 + 1/4 + 1/8 + 1/16....ya know, GEOMETRIC.

Somebody hasn't passed Course 1 yet....

[DeepPurple]

Who would want a car over a goat anyway. A car can take you places, but a good goat can give you love.

[carrot]

Originally Posted by Da Bears!

Sounds geometric to me.....$1

Yeah, that's what I meant.

[carrot]

Originally Posted by DeepPurple

Who would want a car over a goat anyway. A car can take you places, but a good goat can give you love.

ATGTFWG.

[Happy Eellike Prodigality]

stop it