# In a game of 4-Spot Keno, the player picks 4 numbers from 1 to 80. The casino randomly selects 20

In a game of 4-Spot Keno, the player picks 4 numbers from 1 to 80. The casino randomly selects 20 winning numbers from 1 to 80. If the 4 numbers the player picked are all among the 20 winning numbers, the player receives \$120. If three of the 4 numbers are winning numbers, the player receives \$3. If two of the 4 numbers are winning numbers, the player receives \$1. If only one or none are winning numbers, the player receives \$0. It costs \$1 to play the game. The (approximate) probabilities of picking 4, 3, or 2 winning numbers are given in the table below.

Number of winning numbers picked 0 or 1 2 3 4
Payout \$0 \$1 \$3 \$120
Net profit = Payout —\$1 —\$1 \$0 \$2 \$119
Probability ? 0.21264 0.04325 0.00306
Required:
a. What is the probability that the payout is \$0?
b. Compute the expected value of the net profit.
c. Compute the standard deviation of the net profit.
d. If one plays the game 100 times, what is the expected total net profit?
e. What is the standard deviation of the total net profit? Note the outcomes of different games are independent of each other as the winning numbers are selected independently each time.