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Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
To express values in units of standard deviations from the mean
B.
To make every value positive
C.
To remove all outliers
D.
To convert continuous values to categories
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Correct Answer: A. To express values in units of standard deviations from the mean
Explanation:
Standardization centers at zero and scales by the standard deviation.
Choose an option to check your answer.
A.
They always indicate missing data
B.
Logarithms only accept integers
C.
The transformation changes sample size
D.
The ordinary real-valued logarithm is undefined for them
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Correct Answer: D. The ordinary real-valued logarithm is undefined for them
Explanation:
Real logarithms require strictly positive inputs.
Choose an option to check your answer.
A.
Multiplication by zero
B.
Alphabetical sorting
C.
A logarithmic transformation
D.
Replacing all values with ranks only
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Correct Answer: C. A logarithmic transformation
Explanation:
The logarithm compresses large positive values more than small ones.
Choose an option to check your answer.
A.
Small values are more extreme
B.
Large values extend farther from the center than small values
C.
All observations are equal
D.
There are no high observations
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Correct Answer: B. Large values extend farther from the center than small values
Explanation:
A right tail stretches toward larger values.
Choose an option to check your answer.
A.
The data may contain distinct subgroups or a recording discontinuity
B.
The mean is necessarily zero
C.
The sample must be normally distributed
D.
The graph cannot represent numeric data
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Correct Answer: A. The data may contain distinct subgroups or a recording discontinuity
Explanation:
Gaps can reflect real subpopulations, thresholds, censoring, or data errors.
Choose an option to check your answer.
A.
A category bar chart
B.
A pie chart
C.
A frequency table of names
D.
A normal Q-Q plot
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Correct Answer: D. A normal Q-Q plot
Explanation:
Heavy tails create systematic departures at the ends of a normal Q-Q plot.
Choose an option to check your answer.
A.
It increases by that constant
B.
It becomes the constant
C.
It remains unchanged
D.
It is squared
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Correct Answer: C. It remains unchanged
Explanation:
Adding a constant shifts the entire distribution without changing relative distances.
Choose an option to check your answer.
A.
The variance is multiplied by 3
B.
The variance is multiplied by 9
C.
The variance is unchanged
D.
The variance becomes zero
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Correct Answer: B. The variance is multiplied by 9
Explanation:
Variance scales with the square of the multiplicative constant.
Choose an option to check your answer.
A.
Deviations from the mean are squared
B.
It uses only the median
C.
It ignores numerical magnitude
D.
It counts categories alphabetically
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Correct Answer: A. Deviations from the mean are squared
Explanation:
Squaring gives large deviations disproportionately high influence.
Choose an option to check your answer.
A.
A row containing only one variable
B.
A category with the highest frequency
C.
A point outside a histogram bin
D.
An observation with an unusual combination of variable values
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Correct Answer: D. An observation with an unusual combination of variable values
Explanation:
Each individual value may appear ordinary while the joint combination is rare.
Choose an option to check your answer.
A.
A value missing from every record
B.
The most common category
C.
An observation unusual only under specific conditions such as time or group
D.
A point equal to the overall mean
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Correct Answer: C. An observation unusual only under specific conditions such as time or group
Explanation:
Context can make a value normal in one setting but abnormal in another.
Choose an option to check your answer.
A.
Delete every value above the mean
B.
Use robust rules such as IQR fences together with visual inspection
C.
Assume all tail values are errors
D.
Use only the raw sample size
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Correct Answer: B. Use robust rules such as IQR fences together with visual inspection
Explanation:
Robust methods are less distorted by skewness and extremes than mean-based rules.
