Epidemiology Lecture 5 Questions – Flashcards

Ecological studies may not apply to: a. Individuals b. Countries c. Regions d. All of the above.

Researchers manipulate exposure in descriptive studies a. True b. False

What is an example of ecologic fallacy? a. Inaccurate inference from population or community results to the individual. b. Inaccurate inference from the study population to the general population. c. Inaccurate inference from one study population to another study population d. Both B and C e. None of the above

What is/are the limitation(s) of a cross-sectional study? a. It only measures incidence b. The Healthy-Worker effect c. Preponderance of prevalent cases of long duration d. Both B and C

What is the main difference between Descriptive and Analytic studies? a. Descriptive studies only examine individuals b. Descriptive studies are experimental c. Descriptive studies do not manipulate exposure d. None of the above

Which of the following is not a descriptive study? a. Cross-sectional b. Case series c. Ecological d. Experiment

A study examining the effects of a nearby waste disposal site sampled every fifth house in a series of neighborhoods. This is an example of what type of sampling? a. Systematic sampling b. Stratified sampling c. Simple random sampling d. Judgment sampling

Non-probability samples are best used for: a. Rare events b. Complex studies c. Both A and B d. None of the above

What are case-studies/case series MOST used for? a. To detect an outbreak b. To determine causality c. To examine the burden of disease in a population d. To establish formal statistical association

What study design can incorporate consecutive and non consecutive participants? a. Case series b. Ecological c. Cross-sectional None of the above

What is/are the advantage(s) of a cross-sectional study? a. Good generalizability b. Inexpensive c. Can infer causality d. Can infer temporality e. Both A and B

Which of the following is a cross sectional study? a. A study describing the prevalence of smoking among high school students in Harris county. b. To determine the association between smoking and lung cancer, a researcher compared the smoking histories of 500 subjects with lung cancer and 1000 subjects without lung cancer. c. Two groups of elderly subjects - one group vaccinated, the other group unvaccinated were studied to determine the long-term effectiveness of influenza vaccines in elderly people. d. None of the above.

To study the association between knowledge and behaviors related to HIV in high school students, a questionnaire to assess knowledge about prevalence, causes and individual susceptibility to HIV and practice of risky sexual behaviors was administered. This is an example of which type of study? a. Case series b. Case-control c. Cross-sectional d. None of the above

A study that examines the death rates from colon cancer in each of the 50 U.S states in relation to the average percentage of residents in each state undergoing colonoscopy screening. This is an example of : a.Ecologic b.Cross sectional c.Case control d.Cohort

A study comparing the prevalence of cardiovascular disease in the US with the prevalence of cardiovascular disease in Japan is an example of _____ a.Case series b.Case-control c.Cross-sectional d.Ecological Study

Which of the following is a cross sectional study? a.A study describing the prevalence of depression among adult patients with Rheumatoid Arthritis b.A study describing prevalence of developmental disorders among children with Autism. c.None of the above d.Both A and B

A study describing the 5 cases of West Nile Virus disease in Tarrant County in 2012 is an example of _____ a.Case series b.Case-control c.Cross-sectional d.Ecological Study

A researcher set out to investigate the relationship between three major allergic diseases, asthma, allergic rhinitis (AR), and atopic dermatitis (AD), and psychological and behavioral problems in preschoolers. He conducted a survey using a modified International Study of Asthma and Allergies in Childhood questionnaire to determine the prevalence of symptoms and diagnosed allergic diseases, and a Korean version of the Child Behavior Checklist to assess internalizing, externalizing, and sleep problems among 780 preschoolers. This is a ____study design. a.Case series b.Case-control c.Cross-sectional d.Ecological Study

A study describing the prevalence of childhood obesity in Fort Worth is a Cross-Sectional study. a.True b.False

The major purpose of random assignment in a clinical trial is to: a) Help ensure that study subjects are representative of the general population b) Facilitate double blinding (masking) c) Facilitate the measurement of outcome variables d) Ensure that the study groups have comparable baseline characteristics e) Reduce selection bias in the allocation of treatment

An advertisement in a medical journal stated that "2,000 subjects with sore throats were treated with our new medicine. Within 4 days, 94% were asymptomatic." The advertisement claims that the medicine was effective. Based on the evidence given above, the claim: a) Is correct b) May be incorrect because the conclusion is not based on a rate c) May be incorrect because of failure to recognize a long-term cohort phenomenon d) May be incorrect because no test of statistical significance was used e) May be incorrect because no control or comparison group was involved

The purpose of a double blind or double masked study is to: a) Achieve comparability of treated and untreated subjects b) Reduce the effects of sampling variation c) Avoid observer and subject bias d) Avoid observer bias and sampling variation e) Avoid subject bias and sampling variation

In many studies examining the association between estrogens and endometrial cancer of the uterus, a one-sided significance test was used. The underlying assumption justifying a one-sided rather than a two-sided test is: a) The distribution of the proportion exposed followed a "normal" pattern b) The expectation before doing the study was that estrogens cause endometrial cancer of the uterus c) The pattern of association could be expressed by a straight-line function d) Type II error was the most important potential error to avoid e) Only one control group was being used

In a randomized trial, a planned crossover design: a) Eliminates the problem of a possible order effect b) Must take into account the problem of possible residual effects of the first therapy c) Requires stratified randomization d) Eliminates the need for monitoring compliance and noncompliance e) Enhances the generalizability of the results of the study

A randomized trial comparing the efficacy of two drugs showed a difference between the two (with a P value < .05). Assume that in reality, however, the two drugs do not differ. This is therefore an example of: a) Type I error (α error) b) Type II error (β error) c) 1 − α d) 1 − β e) None of the above

All of the following are potential benefits of a randomized clinical trial, except: a) The likelihood that the study groups will be comparable is increased b) Self-selection for a particular treatment is eliminated c) The external validity of the study is increased d) Assignment of the next subject cannot be predicted e) The therapy that a subject receives is not influenced by either conscious or subconscious bias of the investigator