1. New York City has 750 pedestrian walk buttons that work, and another 2500 that do not work. If a pedestrian walk button is randomly selected in New York City, find P(the button works).
2. In the table below, 400 individuals are classified according to whether they were vaccinated against influenza and whether they were attacked by influenza. If one person is selected at random, find the probability that the person was vaccinated or attacked.

	Vaccinated	Not vaccinated
Attacked	60	85
Not Attacked	190	65

3. In the 107th Congress, the Senate consists of 13 women and 87 men. If a lobbyist for the tobacco industry

randomly selects three different senators, what is the probability that they are all women?

4. In the table below, 400 individuals are classified according to whether they were vaccinated against influenza and whether they were attacked by influenza:

	Vaccinated	Not vaccinated
Attacked	60	85
Not Attacked	190	65

If a person is selected at random, find the probability that the person was attacked, given that the person was vaccinated.

5. A password for a computer consists of three letters of the alphabet followed by four different digits from 0 to 9. How many different passwords are possible?