1. Lesson 8.2.1 – Teacher Notes Standard:
7.SP.A.1 Understand that statistics can be used to gain information about a population by examining a sample of the population; generalizations about a population from a sample are valid only if the sample is representative of that population. Understand that random sampling tends to produce representative samples and support valid inferences.
Full mastery can be expected by the end of the chapter.
Lesson Focus:
The focus of the lesson is to have students critique the validity of data based on the sample surveyed. Problem 8-30 may be skipped as it includes additional vocabulary which may not be needed and therefore may be overwhelming. (8-29 and 8-31)
I can generalize that random sampling tends to produce representative samples and support valid inferences.
Calculator: Yes
Literacy/Teaching Strategy: Think-Pair-Share (8-29)

2. If you want to know what a bowl of soup tastes like, do you need to eat all of the soup in the bowl?  Or can you get a good idea of the taste by trying a small sample? 
When you conduct a survey, it is not usually possible for you to survey every person in the population you are interested in, such as all female teenage shoppers or all of the students at your school.  Instead, statisticians collect information about a sample (a portion) of the population.  However, finding a representative sample (a sample that represents the whole population well) is not easy.

3. Most of the people at the grocery store are adults not students.
8-29. As the social director of the Class Council, Heather would like to survey a few students about their interests. 
When Heather analyzes the results from the
survey, she wants to make claims about the
interests of all of the students in her school. 
If he were to survey only students on the Class Council, for example, it might be hard to make claims about what all students think. Students who are on the Class Council may not have the same social interests as other students. Consider this idea as you think about the samples described below.
If Heather wanted to generalize the opinions of all students at his school, would it make sense to go to the grocery store and survey the people there?  Why or why not?   
No.
Most of the people at the grocery store are adults not students.

4. 8-29. As the social director of the
8-29. As the social director of the Class Council, Heather would like to survey a few students about their interests. 
When Heather analyzes the results from the
survey, she wants to make claims about the
interests of all of the students in her school. 
If he were to survey only students on the Class Council, for example, it might be hard to make claims about what all students think. Students who are on the Class Council may not have the same social interests as other students. Consider this idea as you think about the samples described below.
If she wanted to generalize the opinions of all students at her school, would it make sense to ask all of her friends at school?  Why or why not?  
No.
Most of her friends might have the same opinions and have the same interests.

5. This sample is better than the others, but No.
8-29. As the social director of the Class Council, Heather would like to survey a few students about their interests. 
When Heather analyzes the results from the survey, she wants to make claims about the
interests of all of the students in her school.
If he were to survey only students on the Class Council, for example, it might be hard to make claims about what all students think. Students who are on the Class Council may not have the same social interests as other students. Consider this idea as you think about the samples described below.
If he wanted to generalize the opinions of all students at his school, would it make sense to ask every third person who entered the cafeteria at lunch?  Why or why not?  
This sample is better than the others, but
No.
This still doesn’t include students who bring their own lunch or eat in the cafeteria

6. 8-31. From what population is each of these samples taken
8-31. From what population is each of these samples taken?  Write down the actual population for each of these sampling techniques.
Athletic supporters who are Inter-ested in the topic enough to stop
Better survey but still limited only to Athletic supporters.
All students at school
People who use computers who care
People who like to read or are very smart?
Could represent all students in the
School.

7. The sample did not include teenagers.
8-32. A study at the University of Iowa in 2008 concluded that children that play violent video games are more aggressive in real life.  Children ages 9 to 12 were studied to determine how much they played violent video games; peers and teachers were asked how much these students hit, kicked, and got into fights with other students.
Can you legitimately conclude from this study that teenagers who play violent video games tend to be more aggressive?  Why or why not?     NO
The sample did not include teenagers.

8. Crime rates were not studied.
8-32. A study at the University of Iowa in 2008 concluded that children that play violent video games are more aggressive in real life.  Children ages 9 to 12 were studied to determine how much they played violent video games; peers and teachers were asked how much these students hit, kicked, and got into fights with other students.
Can you legitimately conclude from this study that children ages 9 to 12 who play violent video games are more likely to commit violent crimes?  Why or why not?    NO
Crime rates were not studied.

9. This study does not indicate a relationship
8-32. A study at the University of Iowa in 2008 concluded that children that play violent video games are more aggressive in real life.  Children ages 9 to 12 were studied to determine how much they played violent video games; peers and teachers were asked how much these students hit, kicked, and got into fights with other students.
Can you legitimately conclude from this study that children ages 9 to 12 who play violent video games tend to hit and kick more in school?  NO
This study does not indicate a relationship

10. 8-32. A study at the University of Iowa in 2008 concluded that children that play violent video games are more aggressive in real life.  Children ages 9 to 12 were studied to determine how much they played violent video games; peers and teachers were asked how much these students hit, kicked, and got into fights with other students.
Can you legitimately conclude from this study that playing a lot of violent video games will cause 9 to 12-year-old students to become more violent at school? NO
It can only conclude there is a relationship between the two. It might be that violent students are more attracted to violent video games

12. B.

13. D.

14. B

15. C

16. Practice Not Valid Not Valid
Determine if each sample is valid. If it is not, give a suggestion to make it valid.
A marketing person for a company that manufactures roller coaster reports that 92% of Americans like to ride roller coasters. She based this on the data collected from a survey that was given to people who visited American amusement parks over the course of the summer.
Not Valid
2.The school newspaper reports that 47% of seventh graders at the school have at least two siblings. This is based on data that a student gathered from his 3rd period class.
Not Valid

17. Practice Pro – It is a convenient survey.
3. Give at least one pro and one con for each sampling method. Then state which method is best.
Snacks Stat! is considering introducing a new chip, Seeds ‘n’ Stuff. Your Manager of Surveys has suggested the following four methods for selecting a sample to determine customer demand for this product in the town of 1,500 people:
Method A: Survey the first 25 people in line on a weekday for the noon showing of Monster Mayhem at the local movie theater.
Pro – It is a convenient survey.
Con – Not everyone goes to a matinee
during the week and likes monster movies.

18. Pro – Asking parents with children. Children like snacks - like chip.
3. Give at least one pro and one con for each sampling method. Then state which method is best. Snacks Stat! is considering introducing a new chip, Seeds ‘n’ Stuff. Your Manager of Surveys has suggested the following four methods for selecting a sample to determine customer demand for this product in the town of 1,500 people:
Method B: Survey every 5th person arriving at the local playground on a weekday afternoon until 25 people are questioned.
Pro – Asking parents with children. Children like snacks - like chip.
Con – You are not surveying people who might
not have children or work during the day.

19. Pro – It is a random sample
3. Give at least one pro and one con for each sampling method. Then state which method is best. Snacks Stat! is considering introducing a new chip, Seeds ‘n’ Stuff. Your Manager of Surveys has suggested the following four methods for selecting a sample to determine customer demand for this product in the town of 1,500 people:
Method C: Randomly select 5 citizens from records at town hall. Contact each person and arrange to survey him or her.
Pro – It is a random sample
Con – The sample is not big enough.

20. Pro – It is random and the best of all of them.
3. Give at least one pro and one con for each sampling method. Then state which method is best. Snacks Stat! is considering introducing a new chip, Seeds ‘n’ Stuff. Your Manager of Surveys has suggested the following four methods for selecting a sample to determine customer demand for this product in the town of 1,500 people:
Method D: Randomly select 50 citizens from records at town hall. Contact each person and arrange to survey him or her.
Pro – It is random and the best of all of them.
Con – This does not include people who drive, own
Property or might not be registered to vote.