Page 41 - Probability Demystified

30 CHAPTER 2 Sample Spaces

4 1
c. P(at least 2 boys) ¼ ¼ since at least two boys means two
8 2
or three boys. The outcomes are BBG, BGB, GBB, and BBB.
5.

Fig. 2-9.
4 2
The probability that one marble is white is ¼ since the outcomes
6 3
are WB, WG, BW, and GW.

Tables

Another way to find a sample space is to use a table.
EXAMPLE: Find the sample space for selecting a card from a standard deck
of 52 cards.

SOLUTION:

There are four suits—hearts and diamonds, which are red, and spades and
clubs, which are black. Each suit consists of 13 cards—ace through king.
Hence, the sample space can be shown using a table. See Figure 2-10.

Fig. 2-10.
Face cards are kings, queens, and jacks.
Once the sample space is found, probabilities for events can be computed.