1. 1. Zachary rolled a fair number cube twice. Find the probability of the number cube showing an odd number both times. 2. Larissa rolled a fair number cube twice. Find the probability of the number cube showing the same number both times. 1 4 __ 1 36 ___ Do Now

2. 6/2/2015 12-3 A Making Predictions

3. A prediction - a guess about something in the future. The population is the whole group being surveyed To save time and money, researchers often make predictions based on a sample, which is part of the group being surveyed.

4. survey- a method of collecting information

5. Example 1 A store claims that 78% of shoppers end up buying something. Out of 1,000 shoppers, how many would you predict will buy something? You can write a proportion. Remember that percent means “per hundred.”

6. 100x 100 ____ 78,000 100 ______ = Divide both sides by 100 to undo the multiplication. x = 780 You can predict that about 780 out of 1,000 customers will buy something. Think: 78 out of 100 is how many out of 1,000. 100 x = 78 1,000 100x = 78,000 The cross products are equal.x is multiplied by 100. 78 100 ___ x 1,000 =

7. Example 2 If you roll a number cube 30 times, how many times do you expect to roll a number greater than 2? 2 3 __ x 30 ___ = Think: 2 out of 3 is how many out of 30. 3 x = 2 30 3x = 60 The cross products are equal.x is multiplied by 3. P(greater than 2) = = 4 6 __ 2 3

8. Divide both sides by 3 to undo the multiplication. x = 20 You can expect to roll a number greater than 2 about 20 times. 3x3x 3 __ 60 3 __ =

9. Example 3 Suppose the managers of a second stadium, like the one in the student book, also sell yearly parking passes. The managers of the second stadium estimate that the probability of a person with a pass attending any one event is 50%. The parking lot has 400 spaces. If the managers want the lot to be full at every event, how many passes should they sell?

10. 50 100 ___ 400 x ____ = Think: 50 out of 100 is 400 out of how many? 100 400 = 50 x 40,000 = 50x The cross products are equal.x is multiplied by 50. 40,000 50 ______ 50x 50 ___ = Divide both sides by 50 to undo the multiplication. 800 = x The managers should sell 800 parking passes.

11. 1. The owner of a local pizzeria estimates that 72% of his customers order pepperoni on their on their pizza. Out of 250 orders taken in one day, how many would you predict to have pepperoni? 180 Exit Ticket

12. 2. A bag contains 9 red chips, 4 blue chips, and 7 yellow chips. You pick a chip from the bag, record its color, and put the chip back in the bag. If you do this 100 times, how many times do you expect to remove a yellow chip from the bag? 3. A quality-control inspector has determined that 3% of the items he checks are defective. If the company he works for produces 3,000 items per day, how many does the inspector predict will be defective? 35 90 Exit Ticket

13. 1. Based on a sample survey, it was found that 71% of the students in a school play baseball. Out of 3,100 students, how many would you predict to play baseball? A. 1,800 students B. 1,905 students C. 2,000 students D. 2,201 students

14. 2. A box contains 10 black balls, 6 white balls and 4 red balls. You pick a ball from the box, record its color, and put the ball back in the box. If you do this 120 times, how many times would you expect to remove a white ball from the box? A. 30 times B. 36 times C. 50 times D. 80 times

15. 3. There are 120 apples in a box. 5% of the apples in the box are rotten. Identify the number of rotten apples. A. 5 apples B. 6 apples C. 10 apples D. 12 apples

16. Homework Pg. 745 #1-20 Evens Study quiz tomorrow!