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Questions in this quiz (45)
1A researcher with a medium-sized grant wants to study the relationship between sickness and exposure to in-home treated water or tap water. All studied homes share the same tap water. What study would be used for this?
- ACase-Control Study
- BProspective Cohort Study
- CBefore-After Study
2A researcher wants to survey the prevalence of STIs among female college students at four universities. Two of these universities have large educational and outreach campaigns for sexual protection and testing, while the other two do not. The researcher has very limited time and funds. What study should be used?
- AProspective Cohort
- BCase Control Study
- CCross Sectional Study
3A researcher wants to study whether women who breastfeed have lower rates of breast cancer in later life. Funders would like an analysis within two to three years.
Which study design should the researcher choose and how might she study this relationship?- ARetrospective Cohort
- BProspective Cohort
- CCase Control
4Which study is best for studying multiple exposures and rare diseases?
- ACohort
- BCase Control
- CCross Sectional
5Which study is best for studying multiple outcomes and rare exposures?
- ACross Sectional
- BCase Control
- CCohort
6Which study does not have temporal ambiguity?
- ACross Sectional
- BCohort
- CCase Control
7Which study is expensive by comparison?
- ACross Sectional
- BCase Control
- CCohort
8How would you distinguish an RCT from a Cohort?
- AWhether or not investigators were blinded to exposure status
- BWhether or not participants were assigned exposure
- CWhether or not participants were randomly sampled from a defined population
9Which study starts with prevalent (pre-established) cases?
- ACase Control
- BCross Sectional
- CCohort
10Is prevalence a measure of risk?
- AYes
- BNo
11Can cross sectional studies measure risk?
- AYes
- BNo
12In a cohort study of risk factors for cancer, Lin et al. (1995) recruited 9775 men. Blood samples were taken and frozen at recruitment into the cohort study. Over a follow-up of around 7 years, 29 incident cases of gastric cancer were identified. By this time, a number of authors had published studies suggesting that Helicobacter pylori might be a risk factor for gastric cancer. Since H. pylori can be ascertained through an assay on blood samples, Lin and colleagues decided to exploit their stored samples to test this emerging theory . Between five and eight controls were sampled for each case, giving 220 controls altogether. Laboratory work was much reduced compared with analyzing the entire cohort: 249 assays rather than 9775 were required. What kind of study design is this?
- ARetrospective Cohort
- BCase Cohort
- CNested Case Control
13In a given study, blood samples would be collected over time for all study participants and frozen for storage. Then, the biochemical analysis for specific covariates would be performed on all participants as well as participants in a randomly selected sub-group. What study was this?
- ACase Control
- BNested Case
- CCase Cohort
14What can a Case Control Study Measure?
- AIncidence
- BPrevalence
- COdds Ratio
- DRelative Risk
- EAbsolute Risk
15What study design looks at non-cases from a previously conducted cohort?
- ACase Cohort
- BNested Case Control
- CCase Control
16What study looks at acute effect of exposure?
- ACohort
- BCross Sectional
- CCross Over
17Investigators are looking at people with and without an given (not random) exposure (no follow up involved) from separate populations. What study design is this?
- ASimultaneous non-randomized
- BCase Control
- CProspective Cohort
- DNon randomized cohort
18You work in a hospital and are looking at effects of MRSA. You decide to de-colonize all healthcare workers who are carriers. You want to see if this makes a difference in transmission rates in the hospital. You will measure rates prior to decolonization, wait, and measure again once after decolonization What study design is this?
- AProspective Cohort
- BSimultaneous non-randomized
- CNested Case Control
- DBefore and After study
19At 2 years, diabetes remission had occurred in none of the patients receiving medical therapy, as compared with 15 of 20 (75%) undergoing gastric bypass and 19 of 20 (95%) undergoing biliopancreatic diversion (P<0.001 for both comparisons). There was a significant association between study group and rate of remission. However, since there were no remissions in the medical-therapy group, risk ratios were computed in a more conservative fashion on the assumption that remission had occurred in the 2 patients in the medical-therapy group who dropped out.
According to this, what is the RR of the experimental group vs the control group?- A.09
- B1.4
- C4
- D7.5
20Based on this chart, what is the RR (relative risk/rate ratio) for smokers vs non smokers?
Age Smokers Rate Non-Smokers Rate
All Ages 4.29 3.30- A1.1
- B.9
- C1.3
- D1.4
21What can Cohort studies measure?
- APrevalence
- BIncidence
22Can we measure Attributable Risk from a Cohort study?
- AYes
- BNo
23A study is done to examine whether there is an association between use of multivitamins and risk of coronary artery disease (heart attacks). Compared to people who do not take vitamins, individuals who take daily multivitamins have a relative risk of 0.43. Which of the following is a correct interpretation of this finding?
- AThose who take daily multivitamins have 0.43 times the risk of heart attack compared to those who do not take vitamins.
- BThe risk difference in this study is 43 per 100 multivitamin users.
- CThe incidence of coronary artery disease in those who take multivitamins is 0.43 (or 43%).
24A cohort study is conducted to investigate whether there is an association between alcohol consumption and esophageal cancer. The investigators group the subjects into four risk categories: a) non-drinkers, b) less than two drinks per week, c) less than two drinks per day, d) greater than two drinks per day. Which of the following statements is true regarding calculation of the strength of association in this study?
- AThe most logical approach would be to calculate the attributable risk percent of each of the drinking groups using the non-drinkers as a reference group.
- BThe most logical approach would be to calculate the relative risk of each of the drinking groups using the non-drinkers as a reference group.
- CRelative risk can't be calculated because there is more than one risk category.
- DThe most logical approach would be to calculate the risk difference of each of the drinking groups using the non-drinkers as a reference group.
25In order to discuss the EXCESS RISK caused by a risk factor which of the following should be used?
- AIncidence in the exposed group
- BRisk ratio
- CRisk difference
- DOdds Ratio
26When public health officials are interested in determining the number of cases which could possibly be prevented by eliminating a risk factor, which measure of association would they be interested in?
- AIndidence in the exposed group
- BRisk Ratio
- CRisk Difference
- DOdds Ratio
27In the wound infection study, the incidence in the exposed group was 5.3 per 100. Of this, 4 per 100 could be attributed to having had the incidental appendectomy (the other 1.3 per 100 was the "inherent risk" of the staging laparotomy). Therefore, what is the attributable risk %?
- A.25
- B.75
- C1.3
28The Prevalence of Disease X in a community is increasing, but its incidence remains the same. Which of the following is likely true regarding the survival of those who contract X?
- AIt is decreasing
- BIt is staying the same
- CIt is increasing
- DAll of the Above
- ENone of the Above
29At an initial examination at a clinic, migraines were experienced by 5 of 1000 men and 10 in 1000 women.
The inference that women have 2 times greater risk of migraines than men (adjusting for age) is:- ACorrect
- BMay be incorrect because a ratio has been used to compare male and female rates
- CMay be incorrect because did not distinguish between prevalence and incidence
- DMay be incorrect because there is no case of control data given
30The last 5 years of electronic health records for a community of 120,459 residents are examined. 22% have diagnosis of diabetes. Overall, 5,400 had died in the previous years with the leading cause of death being diabetes.
Which of the following measures can be derived from the above information?- A5 Year Mortality rates due to diabetes
- B5 Year cumulative incidence of diabetes
- C5 year case fatality rate for diabetes
- D5 Year proportionate morality ratio for diabetes
31What is cumulative incidence synonymous with?
- ARelative Risk
- BPrevalence
- CMortality Rate
32Efficacy is used in what study design?
- ACase Control
- BClinical Trial
- CCohort
33Effectiveness is used as a measurement in what study design?
- AClinical Trial
- BCohort
- CCase Control
34Relative Risk can be measured in:
- ANested Case Control
- BCase Cohort
- CProspective Cohort
- DAll of the Above
35An Odds Ratio can be calculated for:
- AClinical Trials
- BSimultaneous Non-Randomized
- CNested Case Control
- DCohorts
- EAll of the above
36If a disease increases in prevalence, how will this effect PPV and NPV of a screening test for it?
- ADecrease PPV, Increase NPV
- BIt will not influence them
- CIt depends
- DDecrease Both
- EIncrease PPV, Decrease NPV
- FIncrease Both
37What does a PPV value of 20% tell us?
- AFor all negative test results, 80% are non-cases
- BFor all positive rest results, 80% are cases
- CFor all negative test results, 20% are non-cases
- DFor all positive test results, 20% are non-cases
- ENone of the Above
38What does an NPV of 90% tell us?
- AFor all who test negative, 90% are cases
- BFor all who test positive, 90% are cases
- CFor all who test negative, 90% are non-cases
- DFor all who test positive, 90% are non-cases
39What does a test Sensitivity of 67% tell us?
- AThe test misses roughly 1/3 of all cases
- BThe test misses roughly 2/3 of all cases
- CThe test has a rate of 1/3 false positives
40What does a Specificity of 53% tell us?
- ARoughly 47% of all negatives are false negatives
- BRoughly 47% of all positives are false positives
- CNeither.
41If a disease is considered a 'notifiable disease' by the CDC, state health departments must report cases to the CDC
- ATrue
- BFalse
42You have been asked to provide PPV and NPV without knowing the actual number of cases and non-cases. Is this possible?
- AYes, as long as I know the prevalence.
- BYes, as long as I know the sensitivity and specificity
- CYes as long as I know both the prevalence and the sensitivity/specificity
- DNo, it is not possible.
43Effect Modification is:
- AA systematic error in design
- BA random error in design
- CA variable that influences the risk relationship in terms of effect.
- DA variable that influences the risk relationship in terms of association
44The difference between confounding variables and effect modification variables is:
- AConfounding variables are 3rd variables that account for all or part of a measured association.
- BEffect modification variables are 3rd variables that influence the magnitude of how an exposure influences a condition.
- CConfounders are associated with exposure and outcome.
- DEffect modifiers are associated with outcome but not exposure
- EAll of the Above
- FNone of the Above
45What is a distinct feature of retrospective vs prospective cohort studies?
- AThe outcome of interest occurred in the past.
- BThe exposure of interest occurred in the past
- CExposed and Unexposed individuals are selected based on previous records.
- DCases and Non-cases are selected based on previous records.
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- Quiz on Untitled, created by Stephanie Mars on 18/12/2016.
- Author
- Stephanie Mars
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