A carnival game offers a $80 cash prize for anyone who can break a balloon by throwing a dart at it.It costs $5 to play and you're willing to spend up to $20 trying to win.You estimate that you have a 8% chance of hitting the balloon on any throw.Find the standard deviation of the number of darts you throw.Assume that throws are independent of each other.
A)0.94
B)0.88
C)0.79
D)1.01
E)0.81

Question

Quizplus · Accepted Answer

The standard deviation is the square root of the variance. The variance is the expected value of the squared deviation from the mean. The mean number of darts thrown is 20/0.08 = 250. The variance is 250*0.08*0.92 = 184. The standard deviation is the square root of 184, which is 13.56.

A Carnival Game Offers a $80 Cash Prize for Anyone