7. What type of study is this? How do you know?
8. Construct the 2x2 table for the data above.
9. Calculate the OR for the effect of vaccination on subsequent influenza. Interpret this number in words.
10. Can you tell if this is statistically significant? Why or why not?
11. Does this seem clinical meaningful to you? Why or why not?
12. How would explain this to a patient?
13. If the vaccine was 100% effective, what would you expect your relative risk to be?
14. Given your answer to #10, What does this tell you about the relationship between the vaccine and influenza or what does this tell you about the causal relationship between the vaccine and subsequent influenza.

PART C.
You are conducting a case-control study to identify predictors of breast cancer screening compliance. Your cases are women who have not attended their recommended mammogram appointments.

Table 1. Demographic characteristics among cases and controls
                                             Cases (n=100)    Controls (n=298)
Age                                              54 +/- 9                53+/-11
Marital status
Married                                           96%                      96%
Education
Primary                                           37%                      32%
Secondary                                     56%                      50%
Higher than secondary                      7%                      18%
History of previous mammogram    33%                      69%
15. Above is part of Table 1 showing variety of demographic factors among cases and controls. What is the purpose of Table 1.
16. When selecting controls, what bias are concerned about?
17. When selecting controls, what factors do you need to consider to minimize the bias identified above?
18. It was found that women who had a mammogram were 50% more likely to have had a well visit in an outpatient setting in the last year. What is relative risk implied by this information?
19. It was also found that the OR for not getting a mammorgram related to income greater than 50,000/yr compared to those with income 20,000/yr was 0.80. How would you interpret this in words?
20. Which of the following ORs are significant?
a. 0.60 (0.40. 1.1)
b. 0.98 (0.97, 0.99)
c. 1.3 (1.1, 1.6)
d. 2.0 (1.0, 3.0)
21. You find a significant crude association between smoking and risk of mammography compliance. However, in multivariate models adjusted for several other variables, this association is no longer significant. What might explain this difference?

Part D.
22. What are the criteria for a screening program to be consider a valuable tool?
23. Give an example of a disease for which a screening test would be useful and explain why.
24. Give an example of a disease for which a screening test would NOT be good and explain why.
25. A patient comes in for an HIV test, and wants to know if she receives a positive test, how likely is it that she actually has an HIV infection. What screening parameter would you want to tell her (sensitivity, specificity, positive predictive value, negative predictive value)? If this number was 84%, what would you tell her in response to her question? Be specific.
26. Now, assume she asks how likely is it that the test will be positive if she in fact has HIV. What parameter is this? No assume this number is 96%, what would you tell her in response?

7. What type of study is this? How do you know? 8. Construct the 2...