CHLH 274 EXAM QUESTIONS AND VERIFIED ACCURATE SOLUTION |GET
IT 100% ACCURATE!!!
specificity - ANSWER-ability of the test to identify only non-diseased individuals who actually do not
have the disease
(d / (b+d))
positive predictive value (PPV) - ANSWER-proportion of individuals screened positive by the test who
actually have the disease
(a / (a+b))
negative predictive value (NPV) - ANSWER-proportion of individuals screened negative by the test who
do not have the disease
(d / (c+d))
accuracy of a screening test: - ANSWER-determined via:
(a+d) / (a+b+c+d)
prevalence - ANSWER-(a+c) / (a+b+c+d)
effects of disease prevalence on the predictive value of a screening test - ANSWER-when the prevalence
of a disease falls, the PPV falls and the NPV rises.
relationship between sensitivity and specificity - ANSWER-to improve sensitivity, the cut point used to
classify individuals as diseased should be moved father in the range of the non-diseased (normals);
to improve specificity, the cute point should be moved father in the range typically associated w the
disease
Procedures to improve sensitivity and specificity - ANSWER-retrain screeners, recalibrate screening
instrument, utilize a different test, utilize more than one test
, Lead Time Bias - ANSWER-perception that the screen-detected case has longer survival because the
disease was identified early
Length Bias - ANSWER-Particularly relevant to cancer screening; tumors identified by screening are
slower growing and have a bette prognosis
Selection Bias - ANSWER-motivated participants have a different probability to disease than do those
who refuse to participate
Infectious Diseases (importance) - ANSWER-significant cause of morbidity and mortality worldwide;
infectious agents are associated w some types of cancer; cause disease outbreaks in institutions
epidemiologic triangle - ANSWER-model used to explain the etiology of infectious diseases; recognizes
three major factors in the pathogenesis of disease: agent, host, and environment
microbial agents of infectious disease - ANSWER-bacteria, viruses, fungal disease, protozoa, helminths,
arthropods
bacteria - ANSWER-once were the leading killers, but now are controlled by antibiotics; remain
significant causes of human illness; TB and salmonellosis are common disease caused by bacteria;
emergence of antibiotic-resistant strains a growing concern
Viruses - ANSWER-viral hepatitis A, herpes, and influenza are caused by viruses
mycoses (fungal diseases) - ANSWER-ringworm and athlete's foot; opportunistic mycoses infect
immunocompromised patients (candidiasis)
Protozoa - ANSWER-cause malaria, amebiasis, and giardiasis
Helminths - ANSWER-found in tropical areas; include intestinal parasites such as roundworms,
pinworms, and tapeworms; are responsible for schistomiasis
IT 100% ACCURATE!!!
specificity - ANSWER-ability of the test to identify only non-diseased individuals who actually do not
have the disease
(d / (b+d))
positive predictive value (PPV) - ANSWER-proportion of individuals screened positive by the test who
actually have the disease
(a / (a+b))
negative predictive value (NPV) - ANSWER-proportion of individuals screened negative by the test who
do not have the disease
(d / (c+d))
accuracy of a screening test: - ANSWER-determined via:
(a+d) / (a+b+c+d)
prevalence - ANSWER-(a+c) / (a+b+c+d)
effects of disease prevalence on the predictive value of a screening test - ANSWER-when the prevalence
of a disease falls, the PPV falls and the NPV rises.
relationship between sensitivity and specificity - ANSWER-to improve sensitivity, the cut point used to
classify individuals as diseased should be moved father in the range of the non-diseased (normals);
to improve specificity, the cute point should be moved father in the range typically associated w the
disease
Procedures to improve sensitivity and specificity - ANSWER-retrain screeners, recalibrate screening
instrument, utilize a different test, utilize more than one test
, Lead Time Bias - ANSWER-perception that the screen-detected case has longer survival because the
disease was identified early
Length Bias - ANSWER-Particularly relevant to cancer screening; tumors identified by screening are
slower growing and have a bette prognosis
Selection Bias - ANSWER-motivated participants have a different probability to disease than do those
who refuse to participate
Infectious Diseases (importance) - ANSWER-significant cause of morbidity and mortality worldwide;
infectious agents are associated w some types of cancer; cause disease outbreaks in institutions
epidemiologic triangle - ANSWER-model used to explain the etiology of infectious diseases; recognizes
three major factors in the pathogenesis of disease: agent, host, and environment
microbial agents of infectious disease - ANSWER-bacteria, viruses, fungal disease, protozoa, helminths,
arthropods
bacteria - ANSWER-once were the leading killers, but now are controlled by antibiotics; remain
significant causes of human illness; TB and salmonellosis are common disease caused by bacteria;
emergence of antibiotic-resistant strains a growing concern
Viruses - ANSWER-viral hepatitis A, herpes, and influenza are caused by viruses
mycoses (fungal diseases) - ANSWER-ringworm and athlete's foot; opportunistic mycoses infect
immunocompromised patients (candidiasis)
Protozoa - ANSWER-cause malaria, amebiasis, and giardiasis
Helminths - ANSWER-found in tropical areas; include intestinal parasites such as roundworms,
pinworms, and tapeworms; are responsible for schistomiasis
