HLTH 503 Final || Questions and 100% Accurate Answers.
True or False? Reliability refers to the ability of a measuring instrument to give consistent results
on repeated trials, regardless of its accuracy. correct answers True
A new screening test for Lyme disease is developed for use in the general population. The
sensitivity and specificity of the new test are 60% and 70%, respectively. Three hundred people
are screened at a clinic during the first year the new test is implemented. Assume the true
prevalence of Lyme disease among clinic attendees is 10%.
Calculate the following value
The predictive value of a positive test is: correct answers 18.2%
True or False? Sensitivity refers to the ability of a screening test to correctly identify all screened
individuals who have a disease. correct answers True
A new antibody test detects serum antibodies against virus X (sensitivity 99%, specificity 90%).
When applied in a group of hospitalized patients diagnosed as having virus X infections, the test
is found to have a positive predictive value of 85%. When used to screen a group of healthy
blood donors for virus X infections, the test is found to have a positive predictive value of 30%.
Which of the following best explains this difference between the positive predictive values?
correct answers The prevalence of virus X infection is higher among the hospital patients than
among blood donors
True or False? Specificity refers to the ability of a screening test to identify only nondiseased
individuals who actually do not have the disease. correct answers True
A new screening test for Lyme disease is developed for use in the general population. The
sensitivity and specificity of the new test are 60% and 70%, respectively. Three hundred people
are screened at a clinic during the first year the new test is implemented. Assume the true
prevalence of Lyme disease among clinic attendees is 10%.
Calculate the following value
The number of false positives is: correct answers 81
The degree of agreement among several trained experts refers to: correct answers inter-judge
reliability
A screening examination was performed on 250 persons for Factor X, which is found in disease
Y. A definitive diagnosis for disease Y among the 250 persons had been obtained previously.
The results are charted below: The sensitivity of this test is expressed as: correct answers 80%
Sensitivity and specificity of a screening test refer to its: correct answers Validity
True or False? Validity is the ability of a measuring instrument to give a true measure. correct
answers True
A test that determines whether disease is actually present is a: correct answers diagnostic test
, A screening examination was performed on 250 persons for Factor X, which is found in disease
Y. A definitive diagnosis for disease Y among the 250 persons had been obtained previously.
The results are charted below: The specificity of this test is expressed as: correct answers 70%
True or False? Incubation period refers to the time between the start of an infection and the
beginning of the period of communicability. correct answers False
True or False? Herd immunity must be 100% to confer protection to a group. correct answers
False
True or False? The presence of an infectious agent is a sufficient cause for outbreaks of
infectious disease to occur. correct answers False
An attack rate is an alternative incidence rate that is used when: correct answers All the above
Schistosomiasis is an example of: correct answers biological agents-helminth
True or False? An enzootic disease among animals is similar to an endemic disease among
humans. correct answers True
A person with an inapparent infection: correct answers can transmit the infection to others
True or False? Antigenicity of an infectious agent is measured by the secondary attack rate.
correct answers False
Which of the following examples involves indirect transmission of disease? correct answers A
and B
True or False? Physical environmental factors in the natural history of disease include weather,
temperature, and biologic components. correct answers False
True or False? If a disease is fatal, virulence can be measured by the case fatality rate. correct
answers True
An outbreak of salmonellosis occurred after an epidemiology department luncheon, which was
attended by 485 faculty and staff. Assume everyone ate the same food items. Sixty-five people
had fever and diarrhea, five of these people were severely affected. Subsequent laboratory tests
on everyone who attended the luncheon revealed an additional 72 cases.
The attack rate of salmonellosis was: correct answers 28.2%
What factors comprise the epidemiologic triangle? correct answers All of the above
The death rate per 100,000 for lung cancer is 7 among non-smokers and 71 among smokers. The
death rate per 100,000 for coronary thrombosis is 422 among non-smokers and 599 among
smokers. The prevalence of smoking in the population is 55%.
True or False? Reliability refers to the ability of a measuring instrument to give consistent results
on repeated trials, regardless of its accuracy. correct answers True
A new screening test for Lyme disease is developed for use in the general population. The
sensitivity and specificity of the new test are 60% and 70%, respectively. Three hundred people
are screened at a clinic during the first year the new test is implemented. Assume the true
prevalence of Lyme disease among clinic attendees is 10%.
Calculate the following value
The predictive value of a positive test is: correct answers 18.2%
True or False? Sensitivity refers to the ability of a screening test to correctly identify all screened
individuals who have a disease. correct answers True
A new antibody test detects serum antibodies against virus X (sensitivity 99%, specificity 90%).
When applied in a group of hospitalized patients diagnosed as having virus X infections, the test
is found to have a positive predictive value of 85%. When used to screen a group of healthy
blood donors for virus X infections, the test is found to have a positive predictive value of 30%.
Which of the following best explains this difference between the positive predictive values?
correct answers The prevalence of virus X infection is higher among the hospital patients than
among blood donors
True or False? Specificity refers to the ability of a screening test to identify only nondiseased
individuals who actually do not have the disease. correct answers True
A new screening test for Lyme disease is developed for use in the general population. The
sensitivity and specificity of the new test are 60% and 70%, respectively. Three hundred people
are screened at a clinic during the first year the new test is implemented. Assume the true
prevalence of Lyme disease among clinic attendees is 10%.
Calculate the following value
The number of false positives is: correct answers 81
The degree of agreement among several trained experts refers to: correct answers inter-judge
reliability
A screening examination was performed on 250 persons for Factor X, which is found in disease
Y. A definitive diagnosis for disease Y among the 250 persons had been obtained previously.
The results are charted below: The sensitivity of this test is expressed as: correct answers 80%
Sensitivity and specificity of a screening test refer to its: correct answers Validity
True or False? Validity is the ability of a measuring instrument to give a true measure. correct
answers True
A test that determines whether disease is actually present is a: correct answers diagnostic test
, A screening examination was performed on 250 persons for Factor X, which is found in disease
Y. A definitive diagnosis for disease Y among the 250 persons had been obtained previously.
The results are charted below: The specificity of this test is expressed as: correct answers 70%
True or False? Incubation period refers to the time between the start of an infection and the
beginning of the period of communicability. correct answers False
True or False? Herd immunity must be 100% to confer protection to a group. correct answers
False
True or False? The presence of an infectious agent is a sufficient cause for outbreaks of
infectious disease to occur. correct answers False
An attack rate is an alternative incidence rate that is used when: correct answers All the above
Schistosomiasis is an example of: correct answers biological agents-helminth
True or False? An enzootic disease among animals is similar to an endemic disease among
humans. correct answers True
A person with an inapparent infection: correct answers can transmit the infection to others
True or False? Antigenicity of an infectious agent is measured by the secondary attack rate.
correct answers False
Which of the following examples involves indirect transmission of disease? correct answers A
and B
True or False? Physical environmental factors in the natural history of disease include weather,
temperature, and biologic components. correct answers False
True or False? If a disease is fatal, virulence can be measured by the case fatality rate. correct
answers True
An outbreak of salmonellosis occurred after an epidemiology department luncheon, which was
attended by 485 faculty and staff. Assume everyone ate the same food items. Sixty-five people
had fever and diarrhea, five of these people were severely affected. Subsequent laboratory tests
on everyone who attended the luncheon revealed an additional 72 cases.
The attack rate of salmonellosis was: correct answers 28.2%
What factors comprise the epidemiologic triangle? correct answers All of the above
The death rate per 100,000 for lung cancer is 7 among non-smokers and 71 among smokers. The
death rate per 100,000 for coronary thrombosis is 422 among non-smokers and 599 among
smokers. The prevalence of smoking in the population is 55%.
