3.1. Discrete Random Variables http://www.ck12.org
Now we just divide the numerator by the denominator.
P( 1 head) =3
8
Remember:
Possible outcomes= 2 nwheren=number of tosses.
Here we have 3 tosses. Therefore,
Possible outcomes= 2 n
Possible outcomes= 23
Possible outcomes= 2 × 2 × 2
Possible outcomes= 8
Note:Thefactorial function (symbol: !)just means to multiply a series of descending natural numbers.
Examples:
4!= 4 × 3 × 2 × 1 = 24
7!= 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040
1!= 1
Note: It is generally agreed that 0!=1. It may seem funny that multiplying no numbers together gets you 1, but it
helps simplify a lot of equations.
Example 3:A coin is tossed 4 times. What are the possible outcomes? What is the probability of getting one head?
Solution: