Question

Multiple Question:

12. The relative risk for dying from lung cancer among smokers is 10. The relative risk for dying from heart disease among smokers is 1.5. The etiologic fraction for lung cancer due to smoking is 0.8 and the etiologic fraction for heart disease due to smoking is 0.2. Based on these finding, we can say that

1. Smoking seems much more likely to be causally related to heart disease than to lung cancer.

2. Smoking seems much more likely to be causally related to lung cancer than to heart disease.

3. Smoking seems to be equally causally related to lung cancer and heart disease.

4. Smoking does not seem to be causally related to either lung cancer or heart disease.

13. When calculating absolute risk difference between exposed and non-exposed groups, epidemiologists can use

1. The incidence rate

2. The prevalence

3. The mortality rate

4. Any of the above

14. The purpose of a double-blind study is to

1. Achieve comparability of cases and controls

2. Avoid observer and interviewee bias

3. Avoid observer bias and sampling variation

4. Avoid interviewee bias and sampling variation

15. An epidemiologist experiment is performed in which one group is exposed to a suspected factor and the other is for individuals are randomly assigned to either the experimental of control arm. The main purpose of randomization is to:

1. Ensure a double-blind study

2. Prevent observer bias with respect to the outcome

3. Make it likely that the two groups will be similar with regard to known and unknown confounding factors.

4. Guarantee comparability of the two groups with regard to other relevant factors.

16. The degree of agreement among several trained experts refer to:

1. Internal consistency

2. Repeated measures

3. Concurrent validity

4. Inter-judge reliability

17. Lead time bias is best described as:

1. An apparently lower survival rate among persons screened compared to an unscreened group

2. An Actually longer survival time for persons identified during a screening program because they were given an effective treatment

3. A similar survival time for persons identified during a screening program relative to persons who are diagnosed by clinical symptom

4. An apparently longer survival time among persons identified during a screening program because they were identified at an earlier stage of their disease

Answer 1

12. Smoking seems much more likely to be causally related to lung cancer than to heart disease.

Reason: The relative risk for dying from lung cancer among smokers is 10. The relative risk for dying from heart disease among smokers is 1.5.

13. The incidence rate.

Reason: Calculating Absolute Risk

Absolute risk is always written as a percentage. It is the ratio of people who have a medical event compared to all of the people who could have an event.

14. Avoid observer bias and sampling variation

Reason: The double-blind procedure helps minimize the possible effects of experimenter bias. Such biases often involve the researchers unknowingly influencing the results during the administration or data collection stages of the experiment. Researchers sometimes have subjective feelings and biases that might have an influence on how the subjects respond or how the data is collected.

15. Make it likely that the two groups will be similar with regard to known and unknown confounding factors.

Reason: The main purpose for using randomization in an experiment is that it automatically controls for all lurking variables. In a randomized controlled experiment, researchers control values of the explanatory variable with a randomization procedure. Then, if we see a relationship between the explanatory variable and response variables, we have evidence that it is a causal one.

16. Inter-judge reliability

Reason: refers to reliability assessments derived from agreement among trained experts.

17. An apparently longer survival time among persons identified during a screening program because they were identified at an earlier stage of their disease.

Lead time is the length of time between the detection of a disease (usually based on new, experimental criteria) and its usual clinical presentation and diagnosis (based on traditional criteria). It is the time between early diagnosis with screening and the time in which diagnosis would have been made without screening.