George Washington University PUBH 6003 1)All of the following are important considerations in considering screening for a particular disease except: Select one: a

George Washington University

PUBH 6003

1)All of the following are important considerations in considering screening for a particular disease except: Select one:

a.            The disease has a detectable pre-clinical phase.

b.            Earlier diagnosis can make a difference in disease prognosis or spread.

c.             The cost is balanced by the benefit.

d.            The tests are acceptable to those who would be screened.

e.            All of the above are important considerations.

Question 2

Most screening tests will show an improvement in apparent survival time simply due to: 

Select one or more:

a.            Lead time bias

b.            Length time bias

c.             Volunteer bias

d.            All of the above

For the following three questions consider this hypothetical information: It can be difficult to differentiate mild dementia from normal memory loss or the temporary effects of illness and/or medications in the elderly. Suppose a study used a Quickie Test to save money. The table below compares the results of this test among a group of non-impaired elderly to test results from a group with mild dementia (as diagnosed by a gold standard)

Question 3

If the researchers used a cutoff of >4 items checked on the QuickieTest as a positive test for mild dementia what would be the sensitivity of the test?

Select one: a. 12%

b. 30%

c. 70%

d. 88%

e.            Can’t be calculated without more information

Question 4

If the researchers used a cutoff of >4 items checked on the QuickieTest as a positive test for mild dementia what would be the specificity of the test?

Select one: a. 100%

b. 87% c. 48%

d. 13%

e. Can’t be calculated without knowing the prevalence

Question 5

If you were to compare the PPV of this test for the study population of unusually healthy older subjects (low risk for dementia) to another population in which mild dementia was much more common

Select one:

a.            The PPV would be the same

b.            The PPV would be higher when prevalence was higher

c.             The PPV would be lower when prevalence was higher

d.            Impossible to make any comparison

Question 6

What is the relationship of the tuberculosis bacillus to clinical tuberculosis? Select one:

a.            Necessary cause

b.            Sufficient cause

c.             Confounder

d.            Effect modifier

e.            Synergism

Question 7

Ionizing radiation, benzene, and certain viruses can each individually cause leukemia without the other two exposures, but only if the exposed individual has a certain genetic deficiency. This genetic deficiency by itself does not cause leukemia, but the disease never occurs in the absence of this genetic factor. The genetic deficiency is:

Select one:

a.            A necessary and sufficient cause

b.            A sufficient but not necessary cause

c.             Neither necessary nor sufficient

d.            A necessary but not sufficient cause

e.            None of the above

Question 8

When considering if an association is causal, refuting this criteria will immediately prove it was NOT causal:

Select one:

a.            That it is plausible

b.            That the sample sizes were large

c.             Coherence

d.            Strength of association

e.            Temporality

Question 9

In public health we almost never see a disease with a     _ cause. Select one:

a.            Sole

b.            Necessary

c.             Indirect

d.            Direct

e.            Component

Question 10 

A cross sectional study showed that smokers were 4 times more likely to be depressed. Considering this study alone what criteria for a causal relationship between smoking and depression is met?

Select one:

a.            That it is plausible

b.            Dose response

c.             Coherence

d.            Strength of association

e.            Temporality

f.             None of the above