# Question regarding probability density function

• February 23rd 2010, 01:28 PM
donald17
Question regarding probability density function
Suppose a fair die is tossed three times. Let X be the number of different faces that appear (so X = 1, 2, 3). Find px(k).
• February 23rd 2010, 02:10 PM
Plato
Quote:

Originally Posted by donald17
Suppose a fair die is tossed three times. Let X be the number of different faces that appear (so X = 1, 2, 3). Find px(k).

There are $6^3$ possible outcomes.
There are $120$ ways to have three different faces.
There are $90$ ways to have two different faces.
There are $6$ ways to have only one face.