In: Statistics and Probability
Problem 10 You draw a card from a deck. If you get a club you get nothing. If you get red card you get $10. If you get a spade you get $15 and get to select another card (without replacement). If the second is another spade you receive an additional $20. You receive nothing for any non-spade card. Create a probability model for this game.
We begin first with listing the outcomes and payoffs
Card | Payout |
Club | $0 |
Red | $10 |
Spade and spade | 15 + 20 = $35 |
Spade and non-spade | 15 + 0 = $15 |
When a spade is drawn there is a chance to draw another card. Hence, we join the chances of drawing the 2nd card along with 1st card.
Probability
Now we join the probability
Card | Probability |
1. Club There are 13 clubs in a deck. Hence, the probability of getting a club out of 52 |
= 0.25 |
2. Red There are 26 reds (hearts and diamonds) in a deck. Hence, the probability to get a red out of 52 |
= 0.5 |
3. Spade and spade | = 0.0588 |
4. Spade and non-spade | = 0.1912 |
For 3 & 4
The events of drawing 1st card and 2nd card are independent. So we multiply the probability of the cards.
There are 13 spades so probability of 1st card being spade =
Since the second card drawn is without replacement. Now in the deck only 51 cards will be left with 12 spades and 39 non-spade cards.
If 2nd card is also spade then the possibility
If 2nd card is a non - spade then the possibility
For a probability model all the outcomes along with their probability have to be listed. The sum of probabilities should be equal to 1.
Card | Payout | Probability |
Club | $0 | 0.25 |
Red | $10 | 0.5 |
Spade and spade | $35 | 0.0588 |
Spade and non-spade | $15 | 0.1912 |
Total | 1 |