1. Do Now
On google classroom

2. Lesson 3.9 Using Studies Wisely

3. Objectives
Identify when it is appropriate to use information from a sample to make an inference about a population and when it is appropriate to make an inference about cause and effect.
Evaluate if a statistical study has been carried out in an ethical manner.

4. Important ideas from the text
Inference: a conclusion reached on the basis of evidence and reasoning

5. Random sample Using a chance process to pick members from population
Why do we take them?
So our sample is representative of population
What conclusion can be made?
Inference about the population: generalize results to whole population

6. Random assignment Subjects assigned to treatments using chance process
Why do we do it?
Create groups roughly equivalent
What conclusion can be made?
Inference about cause and effect: one variable causes changes in the other

7. Practice

8. Example 1
Get all the students in your statistics class to participate in a study. Ask them whether or not they study with music on and divide them into two groups based on their answer to this question.
Random Sample? NO
Random Assignment? NO
Conclusion:
Can’t make inference about population
Can’t make inference about cause and effect
No conclusion!

9. Example 2
Select a random sample of students from your school to participate in a study. Ask them whether or not they study with music on and divide them into two groups based on their answer to this question.
Random Sample? YES
Random Assignment? NO
Conclusion:
Can make inference about population
Can’t make inference about cause and effect
Students in the whole school have lower GPA if they listen to music, but we can’t say causation

10. Example 3
Get all the students in your statistics class to participate in a study. Randomly assign half of the students to listen to music while studying for the entire semester and have the remaining half abstain from listening to music while studying.
Random Sample? NO
Random Assignment? YES
Conclusion:
Can’t make inference about population
Can make inference about cause and effect
Listening to music causes GPA to go down, but only for students in our statistics class

11. Example 4
Select a random sample of students from your school to participate in a study. Randomly assign half of the students to listen to music while studying for the entire semester and have the remaining half abstain from listening to music while studying.
Random Sample? YES
Random Assignment? YES
Conclusion:
Can make inference about population
Can make inference about cause and effect
Listening to music causes GPA to go down, for all students in the whole school

12. Principles of data ethics
Institutional review board
Informed consent
Confidentiality

13. Example
Will people try to stop someone from driving drunk? A television news program hired an actor to play a drunk driver and used a hidden camera to record the behavior of individuals who encountered the driver. Was this study carried out ethically? Explain.