1. The investigators conducted a case-control study about the effects of electronic cigarette exposure on COPD bronchial epithelial cell inflammatory responses. When selecting controls (individuals who did not have COPD bronchial epithelial cell inflammatory responses), the investigators eliminated anyone with heart disease because vaping has cardiac effects. They did not eliminate COPD patients with bronchial epithelial cell inflammatory responses who also had heart disease.

What type of bias could this difference in eligibility criteria produce?

Group of answer choices

a. Selection bias

b. Information bias

c. Confounding

d. Sampling variability

2. Briefly explain why you picked this answer.

3. Researchers conducted a study of alcohol use and thyroid cancer. In this study, pathologists were responsible for examining thyroid biopsies and determining whether the study participant had thyroid cancer. Excessive alcohol consumption is one possible cause of thyroid cancer. The pathologists knew which participants used alcohol and which did not. Which of the following types of bias might you be concerned about?

Group of answer choices

a. Selection bias

b. interview bias

c. Observer bias

d. Recall bias

4. Briefly explain why you picked this answer.