1. “DO NOW” In your notebooks Level 0 All you need is your notebook, calculator, and something to write with on your desk Calculate the “r” value for the following problem with your calculator X124 Y023

2. AGENDA Write down homework  Review previous notes  Study for your Quiz #6 on 12/13/2012  Unit Test is on 12/20/2012 “Observational Studies” Lecture Exit Slip Begin Classwork- due at the end of class Collect HW #9 if you did not turn it in on Friday

3. OBSERVATIONAL STUDIES DECEMBER 10, 2012

4. VOCABULARY TERMINOLOGY Explanatory Variable Response Variable Observational Study Designed Experiment Confounding Variable Retrospective Prospective

5. EXPLANATORY VS. RESPONSE VARIABLES Review from previous lecture Define in your notebooks, level 0, what an explanatory and response variable is In Class Discussion What are your definitions? Examples of each type? How does this relate to what we have already learned?

6. OBSERVATIONAL STUDIES Measures the value of the response variable without attempting to influence the value of either the response or explanatory variables. That is, in an observational study, the researcher observes the behavior of the individuals in the study without trying to influence the outcome of the study. What types of studies would be observational? What would your research question be? How would you collect your data? Limitations/Errors/Biases?

7. DESIGNED EXPERIMENT If a researcher assigns the individuals in a study to a certain group, intentionally changes the value of the explanatory variable, and then records the value of the response variable for each group, the researcher is conducting a designed experiment. Checkpoint: Explanatory variable is.. What types of studies would be designed? What would your research question be? How would you collect your data? Limitations/Errors/Biases?

8. Which Would You Choose? Take 3 minutes to write in your notebooks your response(s), level 0. Go!

9. CONSIDER THIS STUDY…. “Researchers wanted to determine the long-term benefits of the influenza vaccine on seniors aged 65 years and older. The researchers looked at records of over 36,000 seniors for 10 years. The seniors were divided into two groups. Group 1 were seniors who chose to get a flu vaccination shot, and group 2 were seniors who chose not to get a flu vaccination shot. After observing the seniors for 10 years, it was determined that seniors who get flu shots are 27% less likely to be hospitalized for pneumonia or influenza and 48% less likely to die from pneumonia or influenza.”

10. THE RESULTS ARE GREAT…MAYBE? At first glance, this study’s results sound remarkable. Less seniors died when they received the influenza vaccine, but.. The authors of the study admitted that there may be some flaw s in their results. What are your guesses to some of those flaws in this study? How does that impact the results?

11. CONFOUNDING Occurs in a study when the effects of two or more explanatory variables are not separated. Therefore, any relation that may exist between an explanatory variable and the response variable may be due to some other variable or variables not accounted for in the study. What are the confounding variables in the previous study with the seniors?

12. LURKING VARIABLES Define in your notebooks what a lurking variable is Write an example next to your definition What is the lurking variables are in the senior study?

13. KEY POINTS TO REMEMBER Observational studies do not allow a researcher to claim causation, only association. Checkpoint: Define causation Designed experiments are used whenever control of certain variables is possible and desirable. Designed experiments allow the researcher to identify certain cause and effect relationships among the variables in the study. So what is the point of doing an observational study? Consider this type of study: Link between smoking and lung cancer Would you want to participate in a designed study?

14. TYPES OF OBSERVATIONAL STUDIES 1.Cross-Sectional Studies 2.Case-Control Studies 3.Cohort Studies Break Into Groups

15. CROSS-SECTIONAL STUDIES

16. CASE-CONTROL STUDIES

17. COHORT STUDIES