Confused on this one question in Statistics?
In the game of roulette a player gives the casino $7 for a bet on the number 5, the player has a 37/38 probability of losing $7 and a 1/38 probability of making a net gain of $245. (The prize is $252 but the players $7 bet is not returned so the net gain is $245.) If a player bets $7 that the outcome is an odd number, the probability of losing $7 is 20/38 and the probability of making a net gain is of $7 is 18/38. (If a player bets $7 on an odd number and wins, the player is given $14 that includes the bet, so the net gain is $7.
a. If a player bets $7 that the outcome is an odd number, what is the players expected value? (Round to the nearest cent)
回答 (3)
expected value=net win(probability of win)-net lost(probability of losing)
ev(5)=245(1/38)-7(37/38)=-$0.368 about -$0.37
ve(o)=7(18/38)-7(20/38)=-$0.368 (the same as before)
The expected value of both bets is to lose 37 cents per bet.
The expected value is just the sum of each outcome's probability times its net gain.
If the player bets on an odd number, then:
20/38 --> net gain is -7 (a loss of the original bet)
18/38 --> net gain is 7 (additional money received over the original bet).
E(X) = (20/38 * -7) + (18/38 * 7)
E(X) ≈ -0.368421
Answer:
The expected value for the player is -0.368 or about about 36.8 cents lost on each play (on average).
Expected value = ($7 * 18/38) + (-$7 * 20/38).
收錄日期: 2021-04-21 15:10:15
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