Do Now Write the equivalent percent. 1. 2. 3. Write the equivalent fraction. 7. 50% 8. 9. 30% 25% 20% 4. 10% 5. 40% 6. 35% Write the equivalent decimal. 0.5 0.2 0.9

An experiment is an activity involving chance An experiment is an activity involving chance. Each repetition or observation of an experiment is a trial, and each possible result is an outcome. The sample space of an experiment is the set of all possible outcomes.

Example 1: Identifying Sample Spaces and Outcomes Identify the sample space and the outcome shown for each experiment. A. Rolling a number cube Sample space:{1, 2, 3, 4, 5, 6} Outcome shown: 4 B. Spinning a spinner Sample space:{red, green, orange, purple} Outcome shown: green

An event is an outcome or set of outcomes in an experiment. Probability is the measure of how likely an event is to occur. Probabilities are written as fractions or decimals from 0 to 1, or as percents from 0% to 100%.

As likely as not Impossible Certain Unlikely Likely 0% 50% 100% Events with a probability of 0% never happen. 50% Events with a probability of 50% have the same chance of happening as not. 100% Events with a probability of 100% always happen.

You can estimate the probability of an event by performing an experiment. The experimental probability of an event is the ratio of the number of times the event occurs to the number of trials. The more trials performed, the more accurate the estimate will be.

Example 2A: Finding Experimental Probability An experiment consists of spinning a spinner. Use the results in the table to find the experimental probability of the event. Outcome Frequency Green 15 Orange 10 Purple 8 Pink 7 Spinner lands on orange

Example 2B: Finding Experimental Probability An experiment consists of spinning a spinner. Use the results in the table to find the experimental probability of the event. Outcome Frequency Green 15 Orange 10 Purple 8 Pink 7 Spinner does not land on green

Example 3A: Try It Now An experiment consists of spinning a spinner. Use the results in the table to find the experimental probability of each event. Outcome Frequency Red 7 Blue 8 Green 5 Spinner lands on red

Example 3B: Try It Now An experiment consists of spinning a spinner. Use the results in the table to find the experimental probability of each event. Outcome Frequency Red 7 Blue 8 Green 5 Spinner does not land on red

You can use experimental probability to make predictions. A prediction is an estimate or guess about something that has not yet happened.

Example 4A: Quality Control Application A manufacturer inspects 500 strollers and finds that 498 have no defects. What is the experimental probability that a stroller chosen at random has no defects? Find the experimental probability that a stroller has no defects. = 99.6% The experimental probability that a stroller has no defects is 99.6%.

Example 4B: Manufacturing Application A manufacturer inspects 500 strollers and finds that 498 have no defects. The manufacturer shipped 3500 strollers to a distribution center. Predict the number of strollers that are likely to have no defects. Find 99.6% of 3500. 0.996(3500) = 3486 The prediction is that 3486 strollers will have no defects.

Example 5A: Try It Now A manufacturer inspects 1500 electric toothbrush motors and finds 1497 have no defects. What is the experimental probability that a motor chosen at random will have no defects? Find the experimental probability that a motor has no defects. = 99.8%

Example 5B: Try It Now A manufacturer inspects 1500 electric toothbrush motors and finds 1497 have no defects. There are 35,000 motors in a warehouse. Predict the number of motors that are likely to have no defects. Find 99.8% of 35,000. 0.998(35000) = 34930 The prediction is that 34,930 motors will have no defects.

Points to Remember Experimental probability = Probability can be expressed as a fraction, decimal, or percent.

Lesson Quiz: Part I 1. Identify the sample space and the outcome shown for selecting a marble. Sample space: {red, green, yellow} Outcome shown: red

Lesson Quiz: Part II 2. An experiment consists of spinning a spinner. Use the results in the table to find the experimental probability of landing on blue. Outcome Frequency Red 9 Blue 6 Yellow 5

Lesson Quiz: Part III 3. The neighbors’ dog barked at Tana the last 4 out of 5 times she walked by their house. a. What is the experimental probability that the dog barks at Tana when she walks past the house? 80% b. Predict the number of times the dog will bark at Tana if she walks past the house 45 times. 36