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Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
Departures from the null in either direction
B.
Only increases from the null
C.
Only decreases from the null
D.
Only whether the sample size is large
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Correct Answer: A. Departures from the null in either direction
Explanation:
A two-sided alternative allows effects above or below the null value.
Choose an option to check your answer.
A.
When the two groups contain unrelated individuals
B.
When the response is a category name only
C.
When there is no repeated structure
D.
When measurements are linked, such as before and after values from the same subjects
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Correct Answer: D. When measurements are linked, such as before and after values from the same subjects
Explanation:
Pairing accounts for within-subject or matched dependence.
Choose an option to check your answer.
A.
The probability that the null is true
B.
The chosen sample size only
C.
A quantitative measure of the magnitude of a difference or relationship
D.
The number of chart annotations
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Correct Answer: C. A quantitative measure of the magnitude of a difference or relationship
Explanation:
Effect sizes describe how large an observed phenomenon is.
Choose an option to check your answer.
A.
Significant results are always caused by bias
B.
A very small effect can be statistically detectable in a large sample
C.
Practical significance can only be negative
D.
P-values directly measure cost
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Correct Answer: B. A very small effect can be statistically detectable in a large sample
Explanation:
A test addresses evidence against a null value, not whether the effect matters in practice.
Choose an option to check your answer.
A.
Increasing sample size
B.
Increasing measurement noise
C.
Using a smaller true effect
D.
Reducing the significance level while changing nothing else
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Correct Answer: A. Increasing sample size
Explanation:
More observations reduce standard errors and improve signal detection.
Choose an option to check your answer.
A.
The probability that the null is true
B.
The width of a histogram bin
C.
The sample variance divided by the mean
D.
The probability of rejecting the null hypothesis when a specified alternative is true
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Correct Answer: D. The probability of rejecting the null hypothesis when a specified alternative is true
Explanation:
Power equals one minus the Type II error probability for a specified effect.
Choose an option to check your answer.
A.
Rejecting a true null hypothesis
B.
Selecting a significance level
C.
Failing to reject a false null hypothesis
D.
Reporting a confidence interval
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Correct Answer: C. Failing to reject a false null hypothesis
Explanation:
A Type II error misses a real effect.
Choose an option to check your answer.
A.
Failing to reject a false null hypothesis
B.
Rejecting a true null hypothesis
C.
Calculating the wrong sample mean
D.
Using a two-sided alternative
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Correct Answer: B. Rejecting a true null hypothesis
Explanation:
A Type I error is a false positive conclusion under the test framework.
Choose an option to check your answer.
A.
The preselected maximum probability of a Type I error under the testing procedure
B.
The observed sample mean
C.
The power of the test
D.
The confidence interval midpoint
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Correct Answer: A. The preselected maximum probability of a Type I error under the testing procedure
Explanation:
Alpha sets the rejection threshold before examining the result.
Choose an option to check your answer.
A.
Prove the null hypothesis
B.
Increase the p-value to α
C.
Conclude the effect is practically large
D.
Reject the null hypothesis
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Correct Answer: D. Reject the null hypothesis
Explanation:
The result is considered statistically significant at the selected level.
Choose an option to check your answer.
A.
The probability that the null hypothesis is true
B.
The size of the observed effect
C.
The probability, assuming the null hypothesis, of obtaining a result at least as extreme as observed
D.
The probability that the data were collected correctly
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Correct Answer: C. The probability, assuming the null hypothesis, of obtaining a result at least as extreme as observed
Explanation:
A p-value measures compatibility between the data and the null model.
Choose an option to check your answer.
A.
A second version of the same dataset
B.
The competing claim supported when evidence contradicts the null
C.
A requirement that the sample be normal
D.
The probability of a Type I error
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Correct Answer: B. The competing claim supported when evidence contradicts the null
Explanation:
The alternative describes the effect or difference of scientific interest.
