This is the second in a series of lessons on probability in the Math Goodies site. The lesson starts with a series of examples illustrating certain and impossible events for simple experiments such as rolling a die, selecting cards from a deck, spinning a spinner, selecting marbles from a jar, and selecting a student from a class. The examples are followed by a brief general discussion of the inequalities \(P(A) > P(B)\), \(P(A) = P(B)\), \(P(A) = 0\) for an impossible event, and \(P(A) = 1\) for a certain event. Finally, several multiple choice exercises are given.