Block 9 Epidemiology Part 2 MCQ's
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In 1945, there were 1,000 women who worked in a factory painting radium dials on watches. The incidence of bone cancer in these women up to 1975 was compared with that of 1,000 women who worked as telephone operators in 1975. Twenty of the radium dial painters and four of the telephone operators developed bone cancer between 1945 and 1975. This study is an example of a:
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Experimental study
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Case series
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Clinical trial
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Retrospective cohort study
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Case-control study
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Epidemiology is the study of the distribution and determinants of health-related states or events or diseases, and the application of this study to the control of diseases and other health problems. Take the Block 9 Epidemiology part 2 MCQ's below and refresh your memory on the chapter. All the best and keep revising.
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- 2.
The following table gives the results of a screening test for diabetes compared to a confirmatory evaluation (oral glucose tolerance test). The sensitivity of this screening test for diagnosing diabetes is:
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23%
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29%
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63%
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99%
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100%
Correct Answer
A. 23%Explanation
The sensitivity of a test is calculated as the proportion of true positive results (diabetic individuals correctly identified by the test) out of all actual positive cases (both correctly identified and missed by the test).
From the table in the image, we have:
True Positive (correctly identified as diabetic): 34
False Negative (incorrectly identified as not diabetic): 116
We can calculate the sensitivity using the formula:
Sensitivity = {True Positive}/{True Positive} +{False Negative}}
Substituting the values:
Sensitivity = 34/34 + 116 = 34/150 ≈ 0.23
So, the sensitivity of this screening test for diagnosing diabetes is approximately 23%. Therefore, the correct answer is 23%.Rate this question:
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- 3.
The following figure shows the epidemic curve for an outbreak of fever and rash among a group of children at a summer camp. They were exposed to a younger relative of one of the campers with fever and rash who had come to visit on the 9th • The average incubation period for the organism in this outbreak is
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8 days
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12 days
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16 days
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20 days
Correct Answer
A. 8 daysExplanation
To determine the average incubation period for the organism in the outbreak, we need to observe the time interval between the day of exposure and the peak of the epidemic curve. In the graph, the exposure is marked on the 9th, and the peak appears to be around the 17th day.
If we count the days from the 9th to the peak on the 17th:
17 - 9 = 8 days
So, the average incubation period for the organism in this outbreak appears to be 8 days. This is calculated based on the time when the largest group of children started showing symptoms, assuming the most common incubation period will align with this peak in cases.Rate this question:
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- 4.
A comparison of clinically diagnosed versus autopsy-confirmed gastric and peptic ulcers was performed or 100„000 consecutive diseased patients in several large hospitals as shown in the following table, From these data, the sensitivity of clinical diagnosis was:
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1,500/1700
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200/96,000
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95,800/96,000
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1,500/4,000
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2,500/4,000
Correct Answer
A. 1,500/4,000Explanation
The sensitivity of clinical diagnosis was calculated by dividing the number of clinically diagnosed cases of gastric and peptic ulcers (1,500) by the total number of autopsy-confirmed cases (4,000). This gives us the proportion of true positive cases that were correctly identified by the clinical diagnosis.Rate this question:
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- 5.
You would typically use a descriptive study
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For a comparison between a new SSRI drug and Venlafaxine
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To compare the difference between random sampling and alternate sampling methods for assessing the efficacy of [CT and psychotherapy as a treatment for depression patients with psychotic depression
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To document a cluster of Wegener's granulomatosis cases that has recently appeared in your area
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To evaluate the effects of Team Based Learning (TBL) versus didactic lecture
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None of the above
Correct Answer
A. To document a cluster of Wegener's granulomatosis cases that has recently appeared in your areaExplanation
A descriptive study is typically used to document and describe a specific phenomenon or situation. In this case, documenting a cluster of Wegener's granulomatosis cases that has recently appeared in your area would require a descriptive study to gather information about the cases, analyze the data, and provide a detailed description of the cluster. This type of study would help in understanding the characteristics, prevalence, and potential causes of the disease cluster.Rate this question:
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- 6.
Validity can be defined as:
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The degree to which an instrument measures what it is supposed to measure.
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The degree to which results are consistent on a repeat measurement
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A measure of the degree or strength of association between two variables.
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Concerned with measuring the frequency of new cases with reliability
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None of the above
Correct Answer
A. The degree to which an instrument measures what it is supposed to measure.Explanation
Validity refers to the degree to which an instrument or measurement accurately measures what it is intended to measure. It assesses whether the instrument is measuring the specific construct or concept it claims to measure. In other words, it examines whether the instrument is valid for the purpose it is being used for. Validity is important in research and measurement as it ensures that the results obtained are meaningful and accurate.Rate this question:
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- 7.
Reliability can be defined as:
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The degree to which an instrument measures what it is supposed to measure
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The degree to which results are consistent
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A measure of the degree or strength of association between two variables
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Concerned with measuring the frequency of new cases with reliability
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Ensuring that patients all take a test under the same conditions
Correct Answer
A. The degree to which results are consistentExplanation
The correct answer is "the degree to which results are consistent". Reliability refers to the consistency of results obtained from a measurement or assessment tool. In other words, it measures the extent to which the same results can be obtained repeatedly under the same conditions. A reliable instrument or test will produce consistent and stable results over time, indicating that it is measuring the same construct consistently. Reliability is an important aspect of any measurement or assessment tool as it ensures that the results obtained are dependable and trustworthy.Rate this question:
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- 8.
A school district has been using an intelligence test to evaluate students and make important placement decisions, such as who gets placed into gifted and other special education settings. However, a group of psychologists advises the school district that there is a problem with this particular test. More specifically, the criticism is that scores on this test correlate too highly with students socioeconomic status. This criticism most directly suggests a problem with the test's:
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Internal consistency
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Test-retest reliability
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Discriminant validity
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Convergent validity
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Predictive validity
Correct Answer
A. Discriminant validityExplanation
The criticism that scores on the intelligence test correlate too highly with students' socioeconomic status suggests a problem with the test's discriminant validity. Discriminant validity refers to the ability of a test to distinguish between different constructs or variables. In this case, the test is not effectively distinguishing between intelligence and socioeconomic status, indicating a lack of discriminant validity.Rate this question:
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- 9.
California Highway Patrol statistics revealed that more accidents occurred to blue cars than to cars of any other color. The inference that while driving a blue car, one is at higher risk of an accident than while driving a car of another color is
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Correct
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Incorrect, because the comparison is not based on rates
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Incorrect, because no control or comparison group is used
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Incorrect, because no test of statistical significance has been made
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Incorrect, because prevalence is used instead of incidence
Correct Answer
A. Incorrect, because the comparison is not based on ratesExplanation
The answer is B, because the statement only provides information about the number of accidents that occurred in blue cars compared to cars of other colors. It does not mention the rates or proportions of accidents for each color, which is necessary for making a valid comparison. Without considering the rates, it is not possible to determine whether driving a blue car actually puts one at a higher risk of an accident compared to driving a car of another color.Rate this question:
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- 10.
An outbreak of gastritis occurred on a cruise ship. The data in the following table were obtained shortly after the outbreak from a questionnaire completed by everyone on board the ship. What is the relative risk of developing gastritis from herring consumption?
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0:5
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2:0
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2:3
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8:0
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1:0
Correct Answer
A. 2:0Explanation
The relative risk of developing gastritis from herring consumption is 2.0. This means that individuals who consumed herring are twice as likely to develop gastritis compared to those who did not consume herring.Rate this question:
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- 11.
In a study of 500 cases of a disease and 500 controls, the suspected etiological factor is found in 400 cases and 100 controls. The absolute risk of disease in people with the factor is
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Cannot be computed from the data given
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80%
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40%
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16%
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20%
Correct Answer
A. 80%Explanation
In the study, the suspected etiological factor is found in:
400 out of 500 cases (individuals with the disease).
100 out of 500 controls (individuals without the disease).
To determine the absolute risk of the disease in people with the factor, you can calculate the ratio of cases with the factor to the total number of cases.
Absolute Risk = Number of cases with the factor / Total number of cases
Absolute Risk = 400 cases / 500 total cases
Absolute Risk = 0.8 or 80%
So, the absolute risk of the disease in people with the suspected etiological factor is 80%.Rate this question:
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- 12.
Epidemic refers to
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A disease that has a low rate of occurrence but that is constantly present in a community or region
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An attack rate in excess of 10 per 1,000 population
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The occurrence of illness/illnesses of a similar nature, clearly in excess of the normal expectation for that population at that time
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Diseases of the respiratory system that occur seasonally
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The annual case rate per 100,000 population
Correct Answer
A. The occurrence of illness/illnesses of a similar nature, clearly in excess of the normal expectation for that population at that timeExplanation
An epidemic refers to the occurrence of illness/illnesses of a similar nature, clearly in excess of the normal expectation for that population at that time. This means that there is a sudden increase in the number of cases of a particular disease or illness in a specific community or region, which is higher than what is typically expected. It is characterized by a higher-than-usual occurrence of a specific illness, indicating an outbreak or spread of the disease within a population.Rate this question:
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- 13.
Regionville is a community of 100,000 persons. During 1985 there were 1,000 deaths from all causes. All cases of tuberculosis have been found and they total 300 - 200 males and 100 females. During 1985, there were 60 deaths from tuberculosis, 50 of them males. The crude mortality rate for Regionville is
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300 per 100,000
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60 per 1,000
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10 per 1,000
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100 per 1,000
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200 per 1,000
Correct Answer
A. 10 per 1,000Explanation
The crude mortality rate is calculated by dividing the number of deaths by the total population and then multiplying by a constant (usually 1,000 or 100,000) to express the rate per 1,000 or 100,000 people. In this case, there were 1,000 deaths in a population of 100,000. So, the crude mortality rate is 1,000/100,000 = 10 per 1,000.Rate this question:
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- 14.
The mean birth weight of first-born infants of 23 women who smoked more than one pack of cigarettes per day during pregnancy was 200 g lower than those of the first-born infants of 16 women who never smoked, The difference was statistically significant at the 5% level (P<0,05). This means which of the following?
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Smoking during pregnancy retards fetal growth
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The difference observed between mean birth weights was too large to have occurred by chance alone
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The difference observed between mean birth weights could have been easily occurred by chance alone
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The number of patients studied was not sufficient to achieve a conclusive result
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Smoking during pregnancy does not influence fetal growth
Correct Answer
A. The difference observed between mean birth weights was too large to have occurred by chance aloneExplanation
The given information states that the mean birth weight of infants born to women who smoked heavily during pregnancy was significantly lower than those born to women who never smoked. This suggests that smoking during pregnancy retards fetal growth. The fact that the difference in birth weights was statistically significant at the 5% level indicates that it is unlikely to have occurred by chance alone. Therefore, the correct answer is that the difference observed between mean birth weights was too large to have occurred by chance alone.Rate this question:
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- 15.
An outbreak of gastritis occurred on the Northern Star cruise ship traveling from New York to Nassau. The data in the table below was obtained from a questionnaire completed by everyone on board the ship shortly after the outbreak. Data from an Outbreak of Gastritis on the Northern Star Cruise Shuzii Given this information, what is the relative risk of developing gastritis from Shrimp and rice on the Northern Star Ship?
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5.0
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1.0
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3.2
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2,0
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7.5
Correct Answer
A. 2,0Explanation
The relative risk of developing gastritis from Shrimp and rice on the Northern Star ship is 2.0. This is calculated by dividing the probability of developing gastritis among those who ate Shrimp and rice (200/1200) by the probability of developing gastritis among those who did not eat Shrimp and rice (100/1500). The result is 2.0, indicating that those who ate Shrimp and rice are twice as likely to develop gastritis compared to those who did not eat it.Rate this question:
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- 16.
You would typically use a descriptive study
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For a comparison between a new SSR1 drug and Venlafaxine
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To compare the difference between random sampling and alternate sampling methods for assessing the efficacy of ECT and psychotherapy as a treatment for depression patients with psychotic depression
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To document a cluster of Wegener's granulomatosis cases that has recently appeared in your area
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To evaluate the effects of Team Based Learning (TBL) versus didactic lecture
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None of the above
Correct Answer
A. To document a cluster of Wegener's granulomatosis cases that has recently appeared in your areaExplanation
A descriptive study is typically used to document and describe a phenomenon or situation. In this case, the study is focused on documenting a cluster of Wegener's granulomatosis cases that have recently appeared in the area. The study aims to gather information about the cases, their characteristics, and any potential patterns or trends. This type of study would not involve comparing different treatments or assessing efficacy, but rather collecting data to better understand the occurrence of the disease in the area.Rate this question:
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.JPG "The following table gives the results of a screening test for diabetes compared to a confirmatory evaluation (oral glucose tolerance test).
The sensitivity of this screening test for diagnosing diabetes is:")
.JPG "The following figure shows the epidemic curve for an outbreak of fever and rash among a group of children at a summer camp. They were exposed to a younger relative of one of the campers with fever and rash who had come to visit on the 9th •
The average incubation period for the organism in this outbreak is")
.JPG "A comparison of clinically diagnosed versus autopsy-confirmed gastric and peptic ulcers was performed or 100„000 consecutive diseased patients in several large hospitals as shown in the following table,
From these data, the sensitivity of clinical diagnosis was:")
.JPG "An outbreak of gastritis occurred on a cruise ship. The data in the following table were obtained shortly after the outbreak from a questionnaire completed by everyone on board the ship.
What is the relative risk of developing gastritis from herring consumption?")
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Current Version
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Aug 22, 2024Quiz Edited by
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May 07, 2012Quiz Created by
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