PUBHEPI 2410 EXAM 2 QUESTIONS WITH VERIFIED SOLUTIONS LATEST UPDATE 2026

PUBHEPI 2410 EXAM 2 QUESTIONS WITH VERIFIED SOLUTIONS LATEST UPDATE 2026 Which type of studies typically take a snapshot of a population at a single point in time and therefore usually measures the disease prevalence, exposure prevalence, or relationship between the two? a. case-control study b. cohort study c. cross-sectional study d. ecological study - Answers c. cross-sectional study The main disadvantage of using which type of controls is the difficulty in determining appropriate illnesses for inclusion? a. dead controls b. friend/spouse/relative controls c. hospital and clinic controls d. population-based controls - Answers c. hospital and clinic controls T/F: Observational studies take advantage of the fact that people expose themselves to noxious or healthy substances through their personal habits. - Answers True Which type of observational study examines one or more health effects/outcomes of exposure to a single agent? a. cohort study b. case-control study c. ecological study d. cross-sectional study - Answers a. cohort study Which of the following is a method of sampling a population in which researchers identify and enroll cases of disease and a sample of the source population that gave rise to the cases? a. case-control study b. ecological study c. randomized clinical trial d. cohort study - Answers a. case-control study The high degree if validity in which type of study stems mainly from the investigator's ability to randomize subjects to either the treatment group or the comparison group and thereby control for distortions produced by confounding variables? a. cohort study b. case-crossover study c. ecological study d. experimental study - Answers d. experimental study Which type of study evaluates an association using the population rather than the individual as the unit of analysis? a. ecological study b. cross-sectional study c. case-control study d. cohort study - Answers a. ecological study The exposed group can also be referred to as which of the following? a. control group b. comparison group c. index group d. reference group - Answers c. index group The Seven Countries study, which examined the relationship between lifestyle, diet, and coronary heart disease in 7 counties, is an example of which study design? a. case-control b. ecologic c. case report d. cross-sectional - Answers b. ecologic Epidemiologic studies that examine the role of a suspected factor in the etiology of a disease may be observational or experimental. The most important difference between experimental and observational studies is that in experimental studies: (Choose one answer) a. the study and control groups are equal in size b. the study is prospective c. the investigator determines who shall be exposed to the suspected factor and who shall not d. the study and control groups are always comparable with respect to all factors other than the exposure e. controls are used - Answers c. the investigator determines who shall be exposed to the suspected factor and who shall not An important weakness of cross-sectional studies is: a. we usually identify a large proportion of prevalent cases b. we usually identify a large proportion of incident cases c. cross-sectional studies take a long time to conduct and are expensive d. we can establish temporarily for all types of exposures - Answers a. we usually identify a large proportion of prevalent cases A cross-sectional study is: a. a study where one variable is manipulated by researchers b. a study that takes place at different times and observes changes in one group over time c. a study that takes place at one time and examines the prevalence of exposures and/or health outcomes d. a study that uses an experiment to find out why there are differences in the study groups - Answers c. a study that takes place at one time and examines the prevalence of exposures and/or health outcomes T/F: Associations that are found at the group level can be used to infer that there exists an association at the individual level. - Answers False In a cross-sectional study of the association between alcohol consumption and dementia, the most appropriate effect measure to calculate is: a. risk difference b. relative risk c. odds ratio d. population attributable risk - Answers c. odds ratio The ecological fallacy is: a. bias that might occur because an association observed at the individual level does not necessarily represent the association that exists at an aggregate level b. a framework used to describe ecological theories of human disease c. bias that might occur because an association observed at the aggregate level does not necessarily represent the association that exists at an individual level d. bias that occurs from conducting observational studies - Answers c. bias that might occur because an association observed at the aggregate level does not necessarily represent the association that exists at an individual level An odds ratio of 2.0 calculated in a cross-sectional study suggests: a. the exposure is more common among individuals with the health outcome b. a clinical trial should be next study conducted c. there is no difference in exposure between the study groups d. the exposure is a cause of the health outcome - Answers a. the exposure is more common among individuals with the health outcome This study design looks at a "snapshot" of the burden of disease and exposure in a population of individuals at one point in time. a. cohort studies b. ecologic studies c. case-control studies d. cross-sectional studies - Answers d. cross-sectional studies T/F: The individual is the unit of analysis for ecologic studies. - Answers False The fulfillment of which concept is crucial to the validity of a case-control study? a. selection bias b. would criterion c. case ascertainment d. confounding - Answers b. would criterion T/F: The individual is the unit of analysis for case-control studies - Answers True You are attempting to establish a link between diets high in trans fatty acids and early heart disease. You identify 50 patients with early heart disease and determine through interviews that 25 had diets high in trans fatty acids. You then gather 150 controls who do not have early heart disease but are of similar age, sex, and socioeconomic status and determine that 50 had diets high in trans-fatty acids. Using the data given above, calculate the numeric value of this measure of association. The numeric value is... a. 4.2 b. 3.5 c. 2.0 d. 1.2 - Answers c. 2.0 A case-control study was conducted to evaluate the relationship between aspirin use and the risk of colon cancer. 2,000 cases and 2,000 controls were enrolled in the study. 1,800 of the cases reported using aspirin in the past while 1,200 of the controls reported using aspirin in the past. What measure of association should be calculated to determine the strength of the relationship between aspirin and colon cancer? a. none of the above b. either of the above c. relative risk d. odds ratio - Answers d. odds ratio A case-control study was conducted to evaluate the relationship between aspirin use and the risk of colon cancer. 2,000 cases and 2,000 controls were enrolled in the study. 1,800 of the cases reported using aspirin in the past while 1,200 of the controls reported using aspirin in the past. Using the data given above, calculate the numeric value of this measure of association. The numeric value is... a. 6.0 b. 2.0 c. 0.2 d. 0.6 - Answers a. 6.0 Which of the following are NOT examples of an analytic study design? a. case report b. ecologic c. cohort d. case-control - Answers a, b (case report, ecologic) This study design begins by identifying persons with an outcome of interest and looking back at their exposure. a. case-control studies b. cross-sectional studies c. cohort studies d. ecologic studies - Answers a. case-control studies British investigators conducted a study to compare measles-mumps-rubella (MMR) vaccine history among 1,294 children with pervasive development disorder (e.g., autism and Asperger's syndrome) and 4,469 children without such disorders. (They found no association.) This is an example of which type of study? a. clinical trial b. case-control c. ecologic d. cohort - Answers b. case-control A special cohort would be assembled to examine the effects of which of the following? a. cigarette smoking b. oral contraceptives c. alcohol consumption d. medical procedures - Answers d. medical procedures T/F: Relative risk estimates the strength of association between exposure and disease - Answers True Consider a cohort of 2,000 people, of whom 800 are smokers and 1,200 are non-smokers. The entire cohort is observed for 20 years, and 100 participants develop lung cancer, of who 90 are smokers and 10 are not. What is the incidence rate of lung cancer for smokers in this cohort per 1,000? a. 102.5 per 1,000 b. 112.5 per 1,000 c. 122.5 per 1,000 d. 142.0 per 1,000 - Answers b. 112.5 per 1,000 Consider a cohort of 2,000 people, of whom 800 are smokers and 1,200 are non-smokers. The entire cohort is observed for 20 years, and 100 participants develop lung cancer, of who 90 are smokers and 10 are not. What is the relative risk of lung cancer for smokers to non-smokers in this cohort? a. 13.5 b. 8.3 c. 16.5 d. 12.5 - Answers a. 13.5