Nokea
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.
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Describe the significance for epidemiology of associating the environment with disease causality.
- A. It helps identify environmental risk factors.
- B. It proves that diseases are not contagious.
- C. It eliminates the need for clinical trials.
- D. It supports genetic research.
Correct Answer: A
Rationale: Linking the environment to disease causality allows for targeted public health interventions to reduce exposure to harmful factors.
validity stands for.
- A. accuracy
- B. reliability
- C. consistency
- D. all
Correct Answer: A
Rationale: Validity refers to how accurately a method measures what it is intended to measure.
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.
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.
A constant rate of change would be represented by a curved line
- A. Arithmetic-scale line graph
- B. Semilogarithmic-scale line graph
- C. Both
- D. Neither
Correct Answer: A
Rationale: On arithmetic-scale graphs, constant rates appear as straight lines.