3.1. Discrete Random Variables http://www.ck12.org
We can have infinite discrete random variables if we think about things that we know have an estimated number.
Think about the number of stars in the universe. We know that there are not a specific number that we have a way to
count so this is an example of an infinite discrete random variable. Another example would be with investments. If
you were to invest $1000 at the start of this year, you could only estimate the amount you would have at the end of
this year.
Well, how does this relate to probability?
Example 1:Looking at the previous table, what is the probability that the sum of the two dice rolled would be 4?
Solution:
P( 4 ) =
3
36
P( 4 ) =
1
12
Example 2:A coin is tossed 3 times. What are the possible outcomes? What is the probability of getting one head?
Solution: