Epidemiology Midterm Test 3 Latest Updated 2025

A physical examination was used to screen for breast cancer in 2,500 women with biopsy-proven adenocarcinoma of the breast and in 5,000 age- and race-matched control women. The results of the physical examination were positive (i.e., a mass was palpated) in 1,800 cases and in 800 control women, all of whom showed no evidence of cancer at biopsy. The sensitivity of the physical examination was: ______ 69.0 % 72.0 % 76.0 % 84.0 % - Correct Ans-72% A physical examination was used to screen for breast cancer in 2,500 women with biopsy-proven adenocarcinoma of the breast and in 5,000 age- and race-matched control women. The results of the physical examination were positive (i.e., a mass was palpated) in 1,800 cases and in 800 control women, all of whom showed no evidence of cancer at biopsy. The specificity of the physical examination was: ______ 69.0 % 72.0 % 76.0 % 84.0 % - Correct Ans-84.0 % A physical examination was used to screen for breast cancer in 2,500 women with biopsy-proven adenocarcinoma of the breast and in 5,000 age- and race-matched control women. The results of the physical examination were positive (i.e., a mass was palpated) in 1,800 cases and in 800 control women, all of whom showed no evidence of cancer at biopsy. The positive predictive value of the physical examination was: ______ 69.2 % 72.0 % 76.0 % 84.0 % - Correct Ans-69.2 % Nursing Nursing Nursing A screening test is used in the same way in two similar populations, but the proportion of false-positive results among those who test positive in population A is lower than that among those who test positive in population B. What is the likely explanation for this finding? It is impossible to determine what caused the difference The specificity of the test is lower in population A The prevalence of disease is lower in population A The prevalence of disease is higher in population A The specificity of the test is higher in population A - Correct Ans-The prevalence of disease is higher in population A A physical examination and an audiometric test were given to 500 persons with suspected hearing problems, of whom 300 were actually found to have them. The results of the examinations were as follows: PHYSICAL EXAMINATION HEARING PROBLEMS Result Present Absent Positive 240 40 Negative 60 160 AUDIOMETRIC TEST HEARING PROBLEMS Result Present Absent Positive 270 60 Negative 30 140 Compared with the physical examination, the audiometric test is: Equally sensitive and specific Less sensitive and less specific Less sensitive and more specific More sensitive and less specific More sensitive and more specific - Correct Ans-More sensitive and less specific Two pediatricians want to investigate a new laboratory test that identifies streptococcal infections. Dr. Kidd uses the standard culture test, which has a sensitivity of 90% and a specificity of 96%. Dr. Childs uses the new test, which is 96% sensitive and 96% specific. If 200 patients undergo culture with both tests, which of the following is correct? Dr. Kidd will correctly identify more people with streptococcal infection than Dr. Childs Dr. Kidd will correctly identify fewer people with streptococcal infection than Dr. Childs Nursing Nursing Dr. Kidd will correctly identify more people without streptococcal infection than Dr. Childs The prevalence of streptococcal infection is needed to determine which pediatrician will correctly identify the larger number of people with the disease - Correct Ans-Dr. Kidd will correctly identify fewer people with streptococcal infection than Dr. Childs A colon cancer screening study is being conducted in Nottingham, England. Individuals 50 to 75 years old will be screened with the Hemoccult test. In this test, a stool sample is tested for the presence of blood. The Hemoccult test has a sensitivity of 70% and a specificity of 75%. If Nottingham has a prevalence of 12/1,000 for colon cancer, what is the positive predictive value of the test? 1.1 % 2.2 % 3.3 % 4.4 % - Correct Ans-3.3 % A colon cancer screening study is being conducted in Nottingham, England. Individuals 50 to 75 years old will be screened with the Hemoccult test. In this test, a stool sample is tested for the presence of blood. If the Hemoccult test result is negative, no further testing is done. If the Hemoccult test result is positive, the individual will have a second