1. A specific medication used to prevent strokes, heart attacks, and blood clots requires a different dosage of medication for members of the African American population than the Caucasian population because a specific gene affects the way the drug is metabolized within the body. This is an example of which of the following?

A) Confounding

B) Selection bias

C) Differential bias

D) Effect modification

2. A new and relatively expensive medication is released into the population to treat type II diabetes. A doctor notices that poor patients are less likely to see effects from the medication than more wealthy patients, but after conducting a survey the doctor finds the poor patients are less likely to fully comply with their medication regimen because they cannot afford to take the medication on a regular basis. This is an example of which of the following?

A) Statistical interaction

B) Confounding

C) Selection bias

D) Recall bias

3. Research has found that circumcision has a protective effect and helps prevent HIV in men who have sex with women, but circumcision does not seem to have the same protective effect helping to prevent HIV in men who have sex with men. This is an example of which of the following?

A) Confounding

B) Selection bias

C) Effect modification

D) Recall bias

4. A study is conducted in patients with HIV. The primary outcome is CD4 cell count, which is a measure of the stage of the disease. Lower CD4 counts are associated with more advanced disease. The investigators are interested in the association between vitamin and mineral supplements and CD4 count. A multiple regression analysis is performed relating CD4 count to use of supplements (coded as 1 = yes, 0 = no) and to duration of HIV, in years (i.e., the number of years between the diagnosis of HIV and the study date). For the analysis,

= CD4 count. = 501.41 + 12.67 Supplements - 30.23 Duration of HIV

What is the expected CD4 count for a patient not taking supplements who has had HIV for 5 years?

A) 350.26

B) 67.82

C) 302.47

D) 1

5. The data presented is a multiple logistic regression analysis and the models are shown below. In the models below, the data are coded as follows: p = the proportion of children with a diagnosis of ADHD, Child Exposed and Father's Diagnosis are coded as 1 = yes and 0 = no. What is the odds ratio adjusted for father's diagnosis? (Hint: Use only the appropriate model to find the odds ratio)

(1) = -2.216 + 1.480 Child exposed

(2)Father with diagnosis: = -1.665 + 1.297 Child exposed

(3)Father without diagnosis: = -2.343 + 0.823 Child exposed

(4) = -2.398 + 1.501 Child exposed + 0.906 Father's diagnosis

A) 4.49

B) 7

C) 2.88

D) 1.501

True/False

1. True or False? An r value of -0.3 indicates a strong negative association.

2. True or False? An r value of 0.5 indicates a positive moderate correlation.

3. True or False? A linear regression equation and multiple linear regression equations can be used to calculate y if one is given the x values. However, a logistic regression equation cannot be used to calculate y when one is given x value.

4. True or False? Multiple logistic regression analysis applies when there is a single dichotomous outcome and only one independent variable.

5. True or False? Multivariable methods include a number of specific procedures to simultaneously assess the relationships between several exposure or risk factor variables and a single outcome.