Epi Final Cowan 2020 Quiz Questions
Phase I of clinical trials for a cancer drug involve: A. Initial testing in humans B. Testing with different tumor types C. Comparing survival rates for the new drug versus extant therapies D. None of the above
A. Initial testing in humans
Which of the following statements is most correct? A. A clinical trial is a community trial B. A clinical trial is an intervention study in a clinical setting C. A community trial involves assignment of the interferon at the level of the individual D. Clinical trials involve group-level assignment of the intervention
B. Clinical trial is an intervention study in a clinical setting
T/F: Risk ratio is defined as the ratio of the offs of exposure among the diseased to the odds among the non-diseased.
False
T/F: The term attributable risk is also known as the relative risk.
false
Which of the following is a form of harm that might be suffered by research participants? A/ Physical injury B/ Stress and anxiety C/ Impaired development D/ All of the above
D/ All of the above
Which of the following of Hill's Guidelines when present supports a causal relationship, yet when absent does not nullify it? A/ Dose-Response (Biological gradient) B/ Consistency C/ Biological Plausibility D/ All of the above
D/ All of the above
Which of the following is not a method for controlling the effects of confounding in epidemiologic studies? A/ Randomization B/ Stratification C/ Matching D/ Blinding E/ Restriction
D/ Blinding
To find a factor of causally related to a disease, which of the following conditions must be satisfied at the very least? A/ The factor must be present in all cases of a disease B/ The factor must have been identified by a randomized clinical C/ Animal experiments must confirm the results obtained in human subjects D/ The factor is found more frequently month the diseased than the non-diseased E/ The evidence identifying the factor must derive from studies that are blinded
D/ The factor is found more frequently among diseased than non-diseased
Epidemiologic studies of the rose of suspected factor in the etiology of a disease may be observational or experiment. The essential difference between experimental and observational studies is that in experimental investigations: A/ The study and control groups are equal in size B/ The study is prosepctive C/ The study and control groups are always comparable D/ The investigation determines who shall be exposed to the suspected factor and who shall not
D/ The investigator determines who shall be exposed to the suspected factor and who shall not.
An epidemiologic experiment is preformed in which one group is exposed to a suspected factor and the other is not. All individuals with an odd hospiralization admission number are assigned to the second group. The main purpose of this procedure is to: A/ ensure a double-blind study B/ prevent observer bias with respect to the factor C/ prevent observer bias with respect to the outcome D/ improve the likelihood that the two groups will be comparable tight regard to know and unknown confounding factors E/ guarantee comparability of the two groups with regard to other relevant factors
D/ improve the likelihood that the two groups will be comparable with regard to known and unknown confounding factors
The population etiologic fraction (also known as population attributable risk proportion) is a measure of the proportion of the disease rate in a population attributable to the exposure of interest. This measure of effect is influenced by: A/ Relative risk of the disease in exposed individuals versus unexposed individuals. B/ The prevalence of the disease in the population. C/ The prevalence of the exposure in the population. D/ A and B E/ A and C
E/ A and C
In a survey which uses lay interviewers one person about his or her death and the health of household members, the sources of error include: A/ the person with disease has had no symptoms and is not aware of the disease B/ The respondent provides the information but the interviewer doesn't record it or records it incorrectly C/ The interviewer doesn't ask the questions that he or she is instructed to ask, or asks them incorrectly. D/ the person has had symptoms and has had medical attention but does not know the name of the disease E/ All of the above
E/ All of the above
Surgeons at Hospital A report that the mortality rate at the end of a one-year follow-up after a new coronary bypass procedure is 15%. At Hospital B the surgeons report a one-year mortality rate of 8% for the same procedure. Before concluding that the surgeons at Hospital B have vastly superior skill, which of the following possible confounders would you examine? A/ the severity (stage) of disease of the patients at the two hospitals at baseline B/ the starting point of the one-year follow-up at both hospitals (after operation versus after discharge) C/ Difference in the post-operative care at the two hospitals D/ equally thorough follow-up for mortality E/ All of the above
E/ All of the above
The association between cigarette smoking and lung cancer has been subjected to considerable scrutiny throughout history. Which of the following statements both strengthen the association between cigarette smoking and lung cancer and move the evidence toward the direction of a causal relationship? A/ The risk of lung cancer increases as the daily consumption of cigarettes increases and/or as the duration of smoking lengthens. B/ Ex-smokers have lung cancer indigence rates intermediate between those of nonsmokers and current smokers. C/ Animal experiments have shown an increase incidence of precancerous lesions following tobacco smoke inhalation D/ Prospective studies agree with retrospective studies about the presence and direction of association. E/ All of the above
E/ All of the above.
All of the following are important criteria when making causal inferences except: A/ Consistency with existing knowledge B/ Dose-response relationship C/ Consistency of association in several studies D/ Strength of association E/ Predictive Values
E/ Predictive values
Reliability is the ability of a measuring instrument to five a true measure.
False
T/F: Population-based cohort studies permit investigations of exposures that are uncommon.
False
True/ False: Control groups are always unethical.
False
True/False: Sensitivity refers to a the ability of a screening test to identify only non diseased individuals who actually do not have the disease.
False
True/False: Survey research in which people are asked questions about themselves have no ethical risk.
False
Informed consent should be designed to empower the potential participant to make an informed choice to participate or not to participate in the study.
True
T/F: A comparison group (ie- non exposed) should be used to correctly preform a cohort study.
True
T/F: A study is externally valid or generalizable, if it allows unbiased inferences to the target population.
True
T/F: Cohort studies preserve the temporality of cause (exposure) happening before the effect (disease).
True
T/F: Experimental designs discussed in this class include randomized controlled trials and community trials.
True
T/F: Internal validity refers to the accuracy of comparisons made between study groups in epidemiologic research.
True
T/F: Randomized clinical trials enroll individual subjects and enable randomization of subjects to receive and not to receive the intervention in a clinical setting.
True
T/F: The p-value indicates the probability of obtaining the observed results, or something more extreme, given the null hypothesis is true.
True
T/F: The purpose of matching in a case-control study is to select the controls in such a way that the control group has the same distribution as the cases with respect to certain confounding variables.
True
T/F: The term attributable risk or risk difference is defined as the difference between the incidence rates in exposed and non-exposed groups.
True
T/F: Treatment crossover refers to any change of treatment for a patient in a clinical trial that involves a switch of study treatments.
True
True/ False: Before any research involving humans can be conducted at an institution that receives federal funds, it must be reviewed by an institutional review board.
True
True/False: Not all persons are entitled to the same degree of autonomy according to the principle of respect.
True
True/False: Positive predictive value refers to the probability that a person with a positive test result does have the disease.
True
True/False: Validity refers to the ability of a measuring instrument to give consistent results on repeated trials, regardless of its accuracy.
True
Cohort Study is to risk ratio as: Ecological fallacy is to cross-sectional study genetics is to environment case-control study is to odds ratio
case control study is to odds ratio
Define the risk difference or attributable risk:
(A/A+B)-(C/C+D)
The purpose of randomization is to: A. Reduce error that results from the unequal distribution of important variables across groups B. Reduce error that results from subjects' participation in the trial compared to the general population C. Reduce error that results from the way in which the outcome is assessed D. None of the above
A. Reduce error that results from the unequal distribution of important variables across groups.
IRB members are charged with all of the following except: A/Assessing the generalizability of research findings B/ Assessing whether participants are giving informed consent C/ Anticipating risks and benefits to participants D/ Reviewing the manner by which data will be safeguarded.
A/ Assessing the generalizability of research findings.
A test that determines whether disease is potentially present is a: A/Screening test B/Diagnostic test C/Reliability test D/ None of the above
A/ Screening test
What measures refer to a screening test's accuracy? Sensitivity Specificity Positive Predictive Value Negative Predictive Value
All of the above
An example of active follow-up in cohort studies is: A.Collection and maintenance of data by the federal government at the population level B.A mailed survey to the participant requesting information C.Information gathered from disease registries D.Database containing outcome of interest collected by another organization
B. A mailed survey to the participant requesting information
The purpose of single-blinding study participants in clinical trials is to: A. Reduce error that results from the way in which the outcome is assessed B. Reduce error that results from subjects knowledge of their assignment to study conditions C. Reduce error that results from non-random assignment to study conditions D. None of the above
B. Reduce error that results from subject's knowledge of their assignment to study conditions
When Should researchers consult with the proper authorities about the appropriate procedures for institutional review of their research project? A/ Before submitting the research for publication B/ Before beginning the research project C/ Before testing the last participant in the research projcet D/ Before analyzing the data from the research project
B/ Before beginning the research project.
You are investigating the role of physical activity in heart disease and suggest that physical activity protects against having a heart attack. While presenting these data to your colleagues, someone asks if you have thought about confounders such as factor X. This factor X could have confounded your interpretation of the data if it: A/ is a factor for some other disease, but not heart disease B/ is a factor associated with physical activity and a risk factor for heart disease, but not a part of the pathway by which physical activity affects heart disease. C/ is a part of the pathway by which physical activity affects heart disease D/ Has caused a lack of follow-up of test subjects
B/ Is a factor associated with physical activity and a risk factor for heart disease but not a part of the pathway by which physical activity affects heart disease.
An investigator examined cases of fetal death in 27000 pregnancies and classified mothers according to whether or not they had experienced sexual intercourse within 1 month before delivery. It was found the 11% of the mothers of fetuses that died and 2.5% of the mothers of fetuses that survived had had sexual intercourse during the period. It was concluded that intercourse during the month preceding delivery caused the fetal deaths. This conclusion: A/ Is correct B/ May be incorrect because mothers who had intercourse during the month before childbirth may differ in other important characteristics from those who did not. C/ May be incorrect because there is no comparison group D/ May be incorrect because prevalence rates are used where incidence rates are needed.
B/ May be incorrect because mothers who had intercourse during the month before childbirth may differ in other important characteristics from those who did not.
Exposure to Mycobacterium tuberculosis is a ___________ of Tuberculosis. A/ Sufficient cause B/ Necessary cause C/ Neither a sufficient nor necessary cause D/ All of the above
B/ Necessary cause
Which characteristic of a suitable screening test is influenced by the stability of the state being measured, the technical characteristics of the test method, and between-observer and within-observer agreement among technicians conducting the test? A/ Validity B/ Reliability C/Sensitivity D/ Specificity
B/ Reliability
In a study to determine the incidence of a chronic disease, 150 people were examined at the end of a three-year period. Twelve cases were found, giving a cumulative risk of 8%. Fifty other members of the initial cohort could not be examined: 20 of these 50 could not be examined because they died. Which source of bias may have affected the study? A/Information bias: interviewer/abstractor bias B/ Selection bias: survival bias C/ Information bias: prevarication (lying) bias D/ All of the above
B/ Selection bias: survival bias
Sensitivity and specificity of a screening test refer to its: A/Reliability B/Accuracy C/Yield D/Repeatability
B/Accuracy
In contrast to observational studies, experimental studies are best employed to: A. Generate knowledge about the natural history of disease B. Formulate strategies for prevention C. Test efficacy of prevent or treatment measures D. None of the above
C. Test the efficacy of prevention or treatment measures
A research participant is allowed to withdraw from a study: A/ For any reason as long as it is explained to the researcher. B/ For any reason as long as the researcher gives permission to withdraw C/ For any reason without any explanation D/ Never
C/ For any reason without any explanation
An advertisement for raspberry flavored aureomycin claimed that "out of 1000 children with URI treated with out raspberry flavored aureomycin, 970 were asymptomatic within 72 hours." The inference that for a child with URI, raspberry flavored aureomycin is the treatment of choice is: A/ Correct B/ Incorrect because the comparison is not based on rates C/ Incorrect because no control or comparison group was used D/ Incorrect because no test of statistical significance was made.
C/ Incorrect because no control or comparison group is used
Cross sectional studies reveal that a higher proportion of arizona residents have respiratory disease than residents of other states. Can it be concluded from this that living in arizona causes respiratory disease? A/ yes, the conclusion is correct. B/ No, the conclusion is incorrect because it may not be a representative sample of the population C/ No, the conclusion is incorrect because a temporal relationship where the exposure preceded the disease was not established. D/ No, because respiratory disease was not well defined in this study.
C/ No, the conclusion is incorrect because a temporal relationship where the exposure preceded the disease was not established.
Factor A, B, or C can each individually cause disease X without the other two factors, but is not required in order for disease X to occur. What would factor A, B, or C be considered? A/ Necessary and sufficient cause B/ Necessary, but not sufficient cause C/ Sufficient, but not necessary cause D/ Neither necessary nor sufficient
C/ Sufficient, but not necessary cause
If it is accepted that an observed association is a causal one, an estimate of the impact that a successful preventative program might have can be derived from: A/ Odds ratio B/ higher life expectancy C/ attributable risk D/ prevalence rates
C/ attributable risk
The strategy which is not aimed at reducing selection bias is: A/ Development of an explicit case definition B/Encouragement of high participation rates C/Standardization protocol for structured interviews D/ enrollment of all cases in a defined time and region
C/ standardized protocol for structured interviews
To assess clinical end points, investigators: A. Compare rates of disease B. Compare rates of death C. Compare rates of recovery D. All of the above
D. All of the above
