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AP Statistics: Random Variable Examples WKS #1
Example 1:
Flip 4 coins.
Let random variable X = the number of heads.
Value of X
Probability
1)
P(X = 3) =
2)
P(X  2) =
3)
P(X  2) =
4)
P(1  X  4) =
5)
P(X  1.5)
Example 2:
Date___________________________
0
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2
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At a carnival, a game of chance involves spinning a wheel that is divided into 60 equal
sectors. The sectors are marked as follows:
$20
$10
$5
No Prize
-
1 sector
2 sectors
3 sectors
54 sectors
The carnival owner wants to know the average expected payout for this game and the
amount of variability (as measured by the standard deviation) associated with it.
Example 3:
Refer to the carnival game in the previous example. Suppose the cost to play the game
is $1. What are the player’s expected winnings?
Example 4: A player pays you $5 and draws a card from a deck. If he draws the ace of hearts, you pay him
$100. For any other ace, you pay $10, and for any other heart, you pay $5. If he draws anything else, he loses.
What is the expected payoff? Then find the variance.