#1
In a scatter plot, what does it suggest if the points form a tight cluster around a line that slopes upward from left to right?
There is no correlation
There is a positive correlation
There is a negative correlation
The correlation is undefined
#2
What does a correlation coefficient of 0 indicate?
A perfect positive correlation
No correlation
A perfect negative correlation
A weak positive correlation
#3
What does a correlation coefficient of 1 indicate?
A perfect positive correlation
A perfect negative correlation
No correlation
A weak positive correlation
#4
What does a correlation coefficient of -1 indicate?
A perfect positive correlation
A perfect negative correlation
No correlation
A weak negative correlation
#5
Which of the following correlation coefficients represents no linear relationship between two variables?
#6
What does a correlation coefficient measure?
Strength and direction of the linear relationship between two variables
Strength of the individual variables
Direction of the individual variables
Magnitude of the nonlinear relationship between two variables
#7
Which of the following correlation coefficients represents a perfect negative linear relationship?
#8
What is the range of values for a correlation coefficient?
[-1, 0, 1]
[0, 1]
[-1, 1]
[0, ∞)
#9
Which of the following scatter plots suggests a stronger correlation?
A scatter plot with points forming a loose cluster around a straight line
A scatter plot with points forming a tight cluster around a straight line
A scatter plot with points forming a random pattern
A scatter plot with points forming a straight line sloping downward
#10
If the correlation coefficient between two variables is -0.8, what does this indicate?
A moderate positive correlation
A moderate negative correlation
A strong positive correlation
A strong negative correlation
#11
Which of the following statements about correlation is FALSE?
Correlation implies causation
Correlation measures the strength and direction of a linear relationship
Correlation coefficients range from -1 to 1
A correlation of 0 indicates no linear relationship between variables
#12
What is the formula to calculate the correlation coefficient between two variables X and Y?
cov(X, Y) / (std_dev(X) * std_dev(Y))
(sum(X) * sum(Y)) / n
(sum(X*Y)) / sqrt(sum(X^2) * sum(Y^2))
(sum(X - mean(X)) * (Y - mean(Y))) / sqrt(sum((X - mean(X))^2) * sum((Y - mean(Y))^2))
#13
When is it appropriate to use Pearson correlation coefficient?
When the relationship between variables is linear
When the relationship between variables is nonlinear
When the data is categorical
When the data has outliers
#14
Which of the following statements about correlation is TRUE?
Correlation implies causation
Correlation measures the strength of the individual variables
Correlation coefficients range from -1 to 0
A correlation of -1 indicates a perfect positive correlation
#15
What is the primary limitation of correlation analysis?
It cannot determine causation
It is only applicable to categorical data
It always results in a perfect correlation coefficient
It is not affected by outliers