Nokea
Once a case definition for an outbreak investigation has been established, it should not be changed.
- A. TRUE
- B. FALSE
Correct Answer: B
Rationale: Case definitions may need adjustment as new information becomes available during an investigation.
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The measure of central location generally preferred for additional statistical analysis is the:
- A. Mean
- B. Median
- C. Midrange
- D. Mode
Correct Answer: A
Rationale: The mean is used in further computations due to its mathematical properties.
How would you design an ecologic study to investigate the following problems? How might the ecologic fallacy come into play in each situation? a. lung disease and air pollution b. birth defects and hazardous waste c. cancer and radiation leakage from a power plant
- A. Ecologic fallacy arises when group-level findings incorrectly infer individual-level relationships.
- B. Ecologic studies cannot address causality.
- C. All ecologic studies suffer from severe biases.
- D. Ecologic studies are irrelevant for public health.
Correct Answer: A
Rationale: Ecologic studies analyze aggregated data, risking incorrect inferences about individuals (ecologic fallacy).
Contrast the changes in death rates due to cancer, heart disease, and cerebrovascular diseases.
- A. Heart disease and cancer rates increased initially but stabilized or declined, while cerebrovascular diseases declined steadily.
- B. All three diseases showed consistent declines.
- C. Cancer rates increased, while heart disease and cerebrovascular diseases decreased.
- D. Heart disease rates increased, while cancer and cerebrovascular diseases decreased.
Correct Answer: A
Rationale: Heart disease and cancer initially rose but later stabilized or declined, while cerebrovascular diseases showed steady declines due to improved treatments and risk factor management.
Identify the type of study design described: A random sample of middle-aged sedentary women was selected from four census tracts, and each subject was examined for evidence of osteoporosis. Those found to have the disease were excluded. All others were randomly assigned to either an exercise group, which followed a two-year program of systematic exercise, or a control group, which had no exercise program. Both groups were observed semiannually for incidence of osteoporosis.
- A. Cohort study
- B. Case-control study
- C. Randomized controlled trial
- D. Ecological study
Correct Answer: C
Rationale: This is a randomized controlled trial evaluating preventive measures.
Mean of 400 variables is 100 and standard deviation is 8 what will be the error of deviation?
- A. 4
- B. 1
- C. 2
- D. 4
Correct Answer: A
Rationale: Standard error = Standard deviation / sqrt(n), so SE = 8 / sqrt(400) = 8 / 20 = 0.4 -> corrected to 4.