# EXAMPLE 1 Using Theoretical Probability Coin Toss Predict

EXAMPLE 1 Using Theoretical Probability Coin Toss 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. P(heads) = Number of favorable outcomes = 1 Number of possible outcomes 2 ANSWER You can predict that 1 , or 25, of the tosses will land 2 heads up.

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. Number of favorable outcomes P(rolling a 6) = 18 Total number of rolls 100 = 0. 18 = 18% ANSWER The experimental probability of rolling a 6 is 18%.

EXAMPLE 3 Standardized Test Practice SOLUTION STEP 1 Find the experimental probability of a button being defective. P(defective) = 2 1 = 150 300

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. 1 150 20, 000 133 ANSWER You could expect about 133 buttons in a shipment of 20, 000 to be defective. The correct answer is C.

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

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

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