1. Copyright©Ed2NetLearning.Inc1 GETTING PREDICTIONS ABOUT PROBABILITY

2. Copyright©Ed2NetLearning.Inc2 PRE-REQUISITE SKILL Solve each proportion. 1.K = 12 9 54 2.24 = m 96 24 3.5 = 30 j 96

3. Copyright©Ed2NetLearning.Inc3 MAKING PREDICTIONS - OBJECTIVE To predict the actions of a larger group using a sample.

4. Copyright©Ed2NetLearning.Inc4 What is a Survey ? A Survey is a method of collecting information. The group being studied is the population. Some times the population is very large. To save time and money, part of the group called a sample is surveyed.

5. Copyright©Ed2NetLearning.Inc5 Sample A good sample is Selected at random, or without preference, Representative of the population, and Large enough to provide accurate data.

6. Copyright©Ed2NetLearning.Inc6 Determine a Good Sample Q. Every sixth person entering a stationary store one day is asked to state whether they support the proposed tax for their district. Determine whether the sample is a good sample. A.i) Asking every sixth person ensures a random survey. ii) The sample should be a representative of a large population; that is, every person living in the school district. iii) The sample is large enough to provide accurate information. So this sample is a good sample.

7. Copyright©Ed2NetLearning.Inc7 Determine a good sample 250 people at the beach in the summer are asked to name their favorite vacation spot. Is this a good sample, explain. No, people at the beach during summer prefer only beach at the vacation spot. So they do not represent a large population.

8. Copyright©Ed2NetLearning.Inc8 Now Your Turn Q. Every seventh person who walked into the school was asked how or she got to school. Determine whether the sample is a good sample.

9. Copyright©Ed2NetLearning.Inc9 Predict More! Q. Miss Candella went to an ice cream shop to conduct a survey. She asked every tenth person who enters into the shop to name his or her favorite dessert. Is this a good sample, explain.

10. Copyright©Ed2NetLearning.Inc10 Make Predictions Using Proportions Juliet asked every 10 th student who walked into school to name their favorite dishes. What is he probability that a student will prefer Chinese dishes? P (Chinese) = number of students that like Chinese dishes number of students surveyed = 18 32 = 0.5625 = 56% Favorite dishes DishesStudents Chinese18 American9 Sausage3 Indian2

11. Copyright©Ed2NetLearning.Inc11 Making Predictions Using Proportions Using the previous table, there are 384 students at the school Juliet attends. Predict how many students prefer Chinese dishes. Use a proportion 18 = s 32 384 32 x s = 18 x 384 s = 6912 = 216 32 Of 384 students, 216 students prefer Chinese dishes S = students who prefer chinese dishes

12. Copyright©Ed2NetLearning.Inc12 Now your turn 1.Hardy asked every 6 th person in the school cafeteria to name the kind of activity he or she would like to have for the school’s outing. A) What is the probability that a student will prefer water park? B) There are 408 students at the school Hardy attends. Predict how many students prefer going to water park? SCHOOL OUTING OUTINGSTUDENTS Amusement park15 Cricket game10 Water park10 Swimming5

13. Copyright©Ed2NetLearning.Inc13 Review A good sample is Selected at random, or without preference, Representative of the population, and Large enough to provide accurate data. We can use the results of a survey to predict and estimate the actions of a larger group.

14. Copyright©Ed2NetLearning.Inc14 Assessment 1.Every 6 th student who walked into the school was asked how she came to school. Determine whether the sample is a good one or not? 2.Every 3 rd shopper at a grocery store is asked whether or not he or she owns a pet. Is it a good sample or not? 3.Use the following information and the table shown. Every 10 th student entering the school was asked which one of the 4 subjects was his or her favorite. 3.What is the probability that any student prefers science? 4.There are 800 students at the school. Prefer how many students prefer science? Favorite Subjects SubjectsStudents Arts2 Mathematics1 Science1 Social science4

15. Copyright©Ed2NetLearning.Inc15 Assessment Use the table and the following information: 5. What is the size of the sample? 6. What is the probability that a student will prefer soccer? 7. What is the probability that a student will prefer cricket? 8.There are 550 students in the school. Predict how many students prefer athletics. 9. Every 20 th student leaving school is asked where the school should hold the year end outing? 10. If 12 out of 50 people surveyed prefer to watch television after 11 pm, how naby people out of 1000 would prefer to watch tv after 11 pm? Favorite Sports Foot ball8 Base ball3 Cricket5 Athletics4

16. Copyright©Ed2NetLearning.Inc16 Great Job!