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All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
The vertical spread changes across values of the predictor
B.
All points lie on one horizontal line
C.
The axes use different fonts
D.
The plot contains exactly two colors
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Correct Answer: A. The vertical spread changes across values of the predictor
Explanation:
Heteroscedasticity means conditional variability is not constant.
Choose an option to check your answer.
A.
The variables follow a perfect circle
B.
Both variables have identical means
C.
The relationship changes direction repeatedly
D.
As one variable increases, the other generally does not decrease
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Correct Answer: D. As one variable increases, the other generally does not decrease
Explanation:
Monotonicity concerns consistent ordering rather than a constant slope.
Choose an option to check your answer.
A.
When both variables are nominal with no order
B.
When there is only one observation
C.
When the relationship is monotonic but nonlinear or strongly affected by outliers
D.
When exact causal effects are required
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Correct Answer: C. When the relationship is monotonic but nonlinear or strongly affected by outliers
Explanation:
Rank-based association does not require a straight-line relationship.
Choose an option to check your answer.
A.
Only differences between group means
B.
The strength of a monotonic relationship using ranks
C.
The probability of survival
D.
The number of clusters in a dendrogram
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Correct Answer: B. The strength of a monotonic relationship using ranks
Explanation:
Spearman correlation replaces values with ranks and assesses monotonic association.
Choose an option to check your answer.
A.
It can greatly increase, decrease, or reverse the apparent association
B.
It can never change correlation
C.
It always makes correlation exactly zero
D.
It changes only the variable names
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Correct Answer: A. It can greatly increase, decrease, or reverse the apparent association
Explanation:
Pearson correlation uses means and products of deviations, both sensitive to extremes.
Choose an option to check your answer.
A.
Correlation cannot be computed from numbers
B.
Scatter plots automatically prove causation
C.
A plot changes the correlation value
D.
Outliers, clusters, and nonlinear patterns can make the coefficient misleading
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Correct Answer: D. Outliers, clusters, and nonlinear patterns can make the coefficient misleading
Explanation:
A single coefficient hides the form and data quality of the relationship.
Choose an option to check your answer.
A.
A tight increasing straight line
B.
A tight decreasing straight line
C.
A symmetric U-shaped relationship
D.
Two identical variables
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Correct Answer: C. A symmetric U-shaped relationship
Explanation:
Positive and negative linear tendencies in a symmetric curve can cancel.
Choose an option to check your answer.
A.
No relationship of any kind
B.
Little or no linear association
C.
Perfect independence in every case
D.
The variables have the same variance
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Correct Answer: B. Little or no linear association
Explanation:
Pearson correlation measures linear association specifically.
Choose an option to check your answer.
A.
A strong positive linear association
B.
A strong negative nonlinear association
C.
No variability in either variable necessarily
D.
Proof that one variable causes the other
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Correct Answer: A. A strong positive linear association
Explanation:
Values near 1 occur when paired points lie close to an increasing straight line.
Choose an option to check your answer.
A.
From 0 to 1 only
B.
From negative infinity to positive infinity
C.
From 0 to the sample size
D.
From -1 to 1
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Correct Answer: D. From -1 to 1
Explanation:
Pearson correlation standardizes linear association to a fixed range.
Choose an option to check your answer.
A.
It can only be negative
B.
It always lies between -1 and 1
C.
Its magnitude depends on the variables' units and scales
D.
It ignores paired observations
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Correct Answer: C. Its magnitude depends on the variables' units and scales
Explanation:
Changing a measurement unit changes covariance numerically.
Choose an option to check your answer.
A.
One variable causes the other
B.
Above-average values of one variable tend to occur with above-average values of the other
C.
The variables have equal means
D.
Both variables must be normally distributed
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Correct Answer: B. Above-average values of one variable tend to occur with above-average values of the other
Explanation:
Covariance is positive when paired deviations from their means are usually of the same sign.
