1. Probability and Conditional Probability

2. Probability Four balls What is the probability of choosing the ball in the red box? Since there are four balls and you are choosing one ball, the probability is 1 out of 4 or ¼. Probability can also be stated as a decimal or a percentage, so this probability also equals.25 or 25%

3. Conditional Probability Given one deck of 52 cards containing 13 cards of each suit (spades, hearts, diamonds, and clubs). What is the probability of receiving a heart, given that you already received two hearts on your first two draws? P (heart card | 2 hearts already drawn) = ?

4. Conditional Probability P (heart card | 2 hearts already drawn) = ? The probability of a heart being drawn is 13 out of 52 = ¼ =.25 = 25%. Since two hearts have already been drawn, there are only 11 heart cards left. Also, there are only 50 cards left in the deck. So P (heart card | 2 hearts already drawn) = 11 out of 50 = 11/50 =.22 = 22%