and Biostatistics for Nursing
Practice Questions 2 [Chapter 9-18]
Book: Epidemiology [Leon Gordis]
Due June 24, 2013
Answer only the questions specified and justify your answers.
Each question is “one point”. Total points=20 (10% of the course grade)
Chapter 9: questions 1, 2, 5
1. In cohort studies of the role of a suspected factor in the etiology of a disease, it is essential that: a. There be equal numbers of persons in both study groups b. At the beginning of the study, those with the disease & those without the disease have equal risks of having the factor c. The study group with the factor and the study group without the factor be representative of the general population d. The exposed & nonexposed groups under study be as similar as possible with regard to possible confounding factors e. Both b and c
According to Gordis, “Often, strong evidence does not exist to justify mounting a large and expensive study for indepth investigation of the role of a specific risk factor in the etiology of a disease. Even when such evidence is available, a cohort of exposed and nonexposed persons often cannot be identified. Generally, we do not have appropriate past records or other sources of data that enable us to conduct a retrospective cohort study; as a result, a long study is required because of the need for extended follow-up of the population after exposure”. (pg. 175) The closer the exposed and nonexposed can be the easier it is to identify the causing factors.
2. Which of the following is not an advantage of a prospective cohort study? a. It usually costs less than a case-control study
b. Precise measurement of exposure is possible
c. Incidence rates can be calculated
d. Recall bias is minimized compared with a case-control study e. Many disease outcomes can be studied simultaneously...