EXAMPLE 1 Using Theoretical Probability Predict the number of times a coin will land heads up in 50 coin tosses. There are two equally likely outcomes when you toss the coin, heads or tails. Coin Toss = 1 2 You can predict that, or 25, of the tosses will land heads up. 1 2 ANSWER P(heads) Number of favorable outcomes Number of possible outcomes =

EXAMPLE 2 Finding Experimental Probability You roll a number cube 100 times. Your results are given in the table below. Find the experimental probability of rolling a 6. P(rolling a 6 ) = Number of favorable outcomes Total number of rolls = 0.18 = 18% The experimental probability of rolling a 6 is 18%. ANSWER

EXAMPLE 3 Standardized Test Practice SOLUTION STEP 1 Find the experimental probability of a button being defective. P(defective) = = 1 150

EXAMPLE 3 Standardized Test Practice STEP 2 Multiply the probability by the total number of buttons in the shipment and round to the nearest whole number , You could expect about 133 buttons in a shipment of 20,000 to be defective. The correct answer is C. ANSWER

GUIDED PRACTICE for Examples 1, 2 and 3 Use the information given in Example 2. What is the experimental probability of rolling a number greater than 3 ? What is the theoretical probability of this event? Number Cube 1. The experimental probability of rolling a number greater than 3 is 48%. ANSWER The theoretical probability of rolling a number greater than 3 is 50%.

GUIDED PRACTICE for Examples 1, 2 and 3 Use the information in Example 3. About how many buttons would you expect to be defective in a shipment of 25,000 buttons? What If? 2. You could expect about 167 buttons in a shipment of 25,000 to be defective. ANSWER