Epidemiology

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· The rapid increase in incidence rates of COVID-19 cases demonstrated the need for a rapid and cheap test to test for infection. Researchers developed a new test, which they called COVT2.0 (COVID-19 Test 2.0), and they compared it to the Gold Standard. Based on the results below, create a two-by-two table.

2. Study results -The Gold Standard test revealed that 115 participants had COVID-19 -the COVT2.0 test reported 4 people as not having COVID-19 when in fact they did have it (“false negatives”) -Scientists reported COVT2.0 had 207 “true negatives” -327 people participated in the study

· Create a two-by-two table and report the above results. (4pts)

	YES disease ‘X’ (Gold Standard)	NO disease ‘X’ (Gold Standard)	Total
New Test + (COVT2.0)
New Test - (COVT2.0)
Total

· Calculate and interpret the sensitivity and specificity of this new screening test. Show your calculations for each. Round to 2 decimal places. Show your calculations. (8 points)

· Calculate the negative predictive value for this new screening test. (2 pts)

16 points

QUESTION 4

1. Match the type of bias to the study examples below. (2 pts each)

- A. B. C. D. E. F.	______ is unlikely to occur in randomized control trials (a.k.a. experimental studies) because the treatment is randomly allocated to the participants.
- A. B. C. D. E. F.	If some participants stop participating in a study and those participants are distinct from those who do remain in a study, then ____ may result.
- A. B. C. D. E. F.	A retrospective cohort study examined the relationship between outdoor air pollution and asthma. Persons with severe cases of asthma were more likely to incorrectly report longer durations of spending time outside while those with mild or no asthma were less likely to misclassify past exposures.
- A. B. C. D. E. F.	A researcher applied different criteria for diagnosing the study result based on whether the participant was exposed or not exposed.

A.	recall bias
B.	informatio bias
C.	assessing outcome bias
D.	nonresponse bias
E.	analytic bias
F.	Selection bias

8 points

QUESTION 5

1. Dozens of studies have shown that tobacco use is associated with lung cancer. This is an example of:

		dose-response relationship
		strength of association
		replication of findings
		biologic plausibility

2 points

QUESTION 6

1. The weakest of the 9 causal guidelines is:

		biologic plausibility
		dose-response relationship
		cessation of exposure
		specificity of the association

2 points

QUESTION 7

1. Of the 4 causal pathways, chronic diseases are an example of:

		neither sufficient nor necessary
		necessary but not sufficient
		necessary and sufficient
		sufficient but not necessary

2 points

QUESTION 8

1. Ecological and cross-sectional studies cannot determine causation. True False

2 points

QUESTION 9

1. A study design in which participants receive two (or more) treatments that are randomly ordered and separated by a washout period represents which type of design…

		cohort study
		factorial
		crossover
		case series

2 points

QUESTION 10

1. In 2016, an unusual number of babies born in Brazil presented with microcephaly (abnormally small head). Researchers enrolled ten babies because little was known about the disease. A comparison group of ten children with normal sized heads was included in the study. Researchers examined the environmental exposures of all babies (and their mothers) included in the study. This is an example of:

a clinical trial with a historical control group

a clinical trial with a nonrandomized control group

a case-control study

a case seri

1. Of the 4 causal pathways, infectious diseases are most often an example of:

		necessary and sufficient
		sufficient but not necessary
		necessary but not sufficient
		neither sufficient nor necessary

2 points

QUESTION 12

1. Case-control studies are the gold standard (i.e., best study design) of epidemiologic research. True False

2 points

QUESTION 13

1. A process whereby the investigator or a computer program assigns subjects to either the treatment or comparison group based on probability is known as…...

		non-compliance
		equipoise
		randomization
		blinding

2 points

QUESTION 14

3. Gentrification, defined as the renovation or improvement of a low-income neighborhood, is associated with the displacement of working class persons. You and your research team want to examine the impacts of gentrification on mental health. Your study begins with a population of 1,000 people in Neighborhood X without mental health issues and you will follow them for 20 years into the future to determine whether there exists a relationship between gentrification and mental health.

· What type of study design is most appropriate? (Be specific.) Why? (3 points)

· Provide 2 advantages and 2 disadvantages of the study design that you chose. (4 points)

· In this example, what type of comparison group is best: internal comparison, external comparison, or general populating data? Why? / points

QUESTION 15

1. Advantages of cohort studies include less vulnerability to bias and better data about exposures. True False

2 points

QUESTION 16

1. Since 1948, the Framingham Heart Study has followed tens of thousands of participants. All participants, including the exposed and not exposed groups, live in Framingham, Massachusetts. The not exposed group is called a/an:

		internal comparison
		equipoise
		external comparison
		counterfactual ideal

2 points

QUESTION 17

1. Explain 1 disadvantage of using hospital controls AND provide an example. points

QUESTION 18

3. Over the last week, it has been reported that 6 women between the ages of 18 and 48 developed a rare blood-clotting disorder one to three weeks after receiving the Johnson & Johnson vaccine. (Note: 7+ million people have received the Jn& J vaccine.) You have been asked to lead a study to examine what factor(s) might have contributed to the blood-clotting disorders.

· In your opinion, what study design is best to understand the relationship between this disorder and the exposure(s)? Explain why it is the best study design in this instance. (3 pts)

· What is a disadvantage of your study design? (2pts)

· Will you include a comparison group? Explain why or why not. (3 pts)

8 points

QUESTION 19

1. Participants in randomized controlled trials (RCTs) determine whether they will be in the treatment group or the comparison group. True False

2 points

QUESTION 20

1. Consider this hypothetical study design: Researchers wanted to determine if an 8-part educational video series could prevent or reduce risky sexual behaviors in college-aged students. The experimental group watched videos about safe sex practices over the course of eight weeks. The control group watched videos about behavioral risk factors linked to non-communicable diseases over the course of eight weeks. Four weeks after the videos were completed (and 12 weeks since the study started), the researchers assessed risky sexual behaviors among study participants. The control group videos can be described as a:

		blinding
		counterfactual ideal
		none of these answers
		placebo

2 points

QUESTION 21

1. An epidemiologic study found that incidence of silicosis among miners in Libby, Montana, was strongly associated with number of years worked in the mine. That is, persons with higher exposure levels had increasingly high risks of disease. Of the 9 causal guidelines, this finding refers to:

		replication of the findings
		dose-response relationship
		biologic plausibility
		consideration of alternative explanations

2 points

QUESTION 22

1. Double blinding in a study means that neither the participant nor the researcher/investigator knows if the participant receives a treatment. True False