HLTH 4200 Week 5 Quiz - Question and Answers (DETAILED)

1. All of the following are types of bias (systematic error) in epidemiological studies EXCEPT: 2. The strategy that is not aimed at reducing selection bias is: 3. For a variable to be a confounder, it must be: 4. All of the following should be considered when assessing causality EXCEPT: 5. Select all that apply. When assessing the results of a study, what are the possible explanations for the observed results? 6. Which of the following is a true statement? 7. If the individuals who participate in a screening program have a different probability of disease from those who do not participate (for example, they may be healthier or sicker; older or younger; employed or not employed), ________ bias would have occurred 8. Suppose that you are in charge of evaluating a newly developed screening test compared to a gold standard. You test 1,000 individuals. Of the 300 who test positive with the gold standard, 285 of them also test positive with the new screening test. Of the 700 who test negative with the gold standard, 7 of them test positive with the new screening test. What is the sensitivity of your new screening test? 9. Suppose that you are in charge of evaluating a newly developed screening test compared to a gold standard. You test 1,000 individuals. Of the 300 who test positive with the gold standard, 285 of them also test positive with the new screening test. Of the 700 who test negative with the gold standard, 7 of them test positive with the new screening test. What is the specificity of your new screening test? 10. A screening examination was performed on 250 persons for Factor X, which is found in disease Y. A definitive diagnosis for disease Y among the 250 persons had been obtained previously.