Q.1 What does a positive correlation between two variables indicate?
As one variable increases, the other decreases
There is no relationship between the variables
As one variable increases, the other also increases
The variables are independent
Explanation - A positive correlation means both variables move in the same direction.
Correct answer is: As one variable increases, the other also increases
Q.2 Which correlation coefficient indicates the strongest relationship?
0.9
-0.7
0.5
-0.3
Explanation - Correlation coefficients range from -1 to 1. The closer to 1 or -1, the stronger the relationship.
Correct answer is: 0.9
Q.3 If the correlation coefficient is 0, what does it imply?
A perfect positive relationship
A perfect negative relationship
No linear relationship
A strong relationship
Explanation - A correlation of 0 indicates no linear relationship, though a non-linear relationship may exist.
Correct answer is: No linear relationship
Q.4 Which of the following methods is commonly used to compute correlation?
Spearman's Rank
Chi-square Test
ANOVA
Regression Analysis
Explanation - Spearman's Rank correlation is used for ordinal data, while Pearson's correlation is used for interval/ratio data.
Correct answer is: Spearman's Rank
Q.5 A negative correlation between study hours and absenteeism means:
More study hours lead to more absenteeism
More study hours lead to less absenteeism
There is no effect of study hours on absenteeism
Absenteeism causes study hours to decrease
Explanation - Negative correlation indicates that as one variable increases, the other decreases.
Correct answer is: More study hours lead to less absenteeism
Q.6 Which correlation coefficient represents a perfect negative correlation?
1
-1
0
0.5
Explanation - A correlation of -1 indicates a perfect negative linear relationship between two variables.
Correct answer is: -1
Q.7 If X and Y have a correlation coefficient of 0.8, what can we say about their relationship?
They have a weak positive linear relationship
They have a strong positive linear relationship
They are independent
They have a strong negative relationship
Explanation - Correlation coefficients closer to 1 indicate a strong positive relationship.
Correct answer is: They have a strong positive linear relationship
Q.8 Which of the following can affect the value of the correlation coefficient?
Outliers
Sample size
Non-linear relationship
All of the above
Explanation - Outliers, sample size, and non-linear relationships can all distort correlation values.
Correct answer is: All of the above
Q.9 Pearson correlation is most suitable for:
Ordinal data
Nominal data
Interval or ratio data
Binary data
Explanation - Pearson correlation measures linear association for continuous interval or ratio data.
Correct answer is: Interval or ratio data
Q.10 Which type of correlation measures the strength of a monotonic relationship?
Pearson
Spearman
Kendall's tau
Both Spearman and Kendall's tau
Explanation - Spearman and Kendall's tau measure monotonic relationships, even if not linear.
Correct answer is: Both Spearman and Kendall's tau
Q.11 A scatter plot of two variables shows a downward trend. What is the expected correlation sign?
Positive
Negative
Zero
Cannot be determined
Explanation - A downward trend indicates that as one variable increases, the other decreases, i.e., negative correlation.
Correct answer is: Negative
Q.12 Which of these correlation coefficients indicates the weakest relationship?
0.2
0.7
-0.6
0.9
Explanation - A correlation closer to 0 indicates a weak linear relationship.
Correct answer is: 0.2
Q.13 Correlation does NOT imply:
Strength of relationship
Direction of relationship
Causation
Association
Explanation - Correlation shows association but does not prove one variable causes the other to change.
Correct answer is: Causation
Q.14 A correlation coefficient of -0.85 implies:
Weak negative correlation
Strong negative correlation
Weak positive correlation
Strong positive correlation
Explanation - Correlation close to -1 indicates a strong negative relationship.
Correct answer is: Strong negative correlation
Q.15 Which of the following pairs is likely to have positive correlation?
Hours studied and exam marks
Exercise hours and weight gain
Rainfall and dry soil
Absenteeism and grades
Explanation - As study hours increase, exam marks are likely to increase, showing positive correlation.
Correct answer is: Hours studied and exam marks
Q.16 Which correlation method is preferable when the data contains outliers?
Pearson
Spearman
None
Both are equally affected
Explanation - Spearman's rank correlation is less sensitive to outliers as it uses ranks instead of raw data.
Correct answer is: Spearman
Q.17 If two variables are perfectly correlated, what is the absolute value of their correlation coefficient?
0
0.5
1
Cannot be determined
Explanation - Perfect correlation corresponds to a correlation coefficient of either 1 (positive) or -1 (negative).
Correct answer is: 1
Q.18 Which of the following is a limitation of correlation analysis?
Cannot detect non-linear relationships
Sensitive to outliers
Does not imply causation
All of the above
Explanation - Correlation has limitations: it only measures linear relationships, can be affected by outliers, and does not imply causation.
Correct answer is: All of the above
Q.19 Which value of correlation indicates a moderate positive linear relationship?
0.9
0.7
0.4
0.1
Explanation - Values around 0.3–0.5 typically indicate moderate positive correlation.
Correct answer is: 0.4
Q.20 When variables X and Y are independent, the correlation coefficient is:
Exactly 1
Exactly -1
Approximately 0
Cannot be predicted
Explanation - Independence implies no linear relationship, so correlation is near 0.
Correct answer is: Approximately 0
Q.21 What type of graph is used to visually assess correlation?
Bar chart
Line graph
Scatter plot
Pie chart
Explanation - Scatter plots display the relationship between two variables and help visualize correlation.
Correct answer is: Scatter plot
Q.22 If a dataset shows a perfect linear trend but correlation is negative, the line slopes:
Upwards
Downwards
Horizontally
Cannot be determined
Explanation - A negative correlation implies a downward-sloping trend line.
Correct answer is: Downwards
Q.23 Which correlation coefficient is more affected by extreme values?
Spearman
Pearson
Kendall's tau
All are equally affected
Explanation - Pearson correlation uses raw values and is sensitive to outliers.
Correct answer is: Pearson
Q.24 If two variables have a correlation of 0.95, what can we infer?
They are independent
They have a weak relationship
They have a strong positive linear relationship
They have a strong negative relationship
Explanation - A correlation close to 1 indicates a strong positive relationship.
Correct answer is: They have a strong positive linear relationship
Q.25 Which of the following is true about Spearman's rank correlation?
It requires normal distribution
It can handle ordinal data
It is unaffected by monotonicity
It is the same as Pearson correlation
Explanation - Spearman correlation is suitable for ordinal data and monotonic relationships.
Correct answer is: It can handle ordinal data