Correlation – Pearson and Spearman - One Line Questions
1.
A perfect positive rank correlation using Spearman's rho would result in a value of: —
1
2.
If the ranks of two variables are identical for all data points, what will be the value of Spearman's rho? —
1
3.
If the ranks of two variables are perfectly reversed (highest rank for one corresponds to lowest for the other), Spearman's rho will be: —
-1
4.
What is the range of possible values for a Pearson correlation coefficient (r)? —
-1 to 1
5.
Which of the following correlation coefficients indicates the strongest linear relationship? —
-0.9
6.
If the Pearson correlation coefficient is 0.8, the coefficient of determination (r-squared) is: —
0.64
7.
When calculating Pearson's r, if one of the variables has zero variance (all values are the same), the correlation coefficient will be: —
Undefined
8.
What does a Pearson correlation coefficient of 0 indicate? —
No linear relationship between the variables.
9.
A scatterplot showing a clear upward trend from left to right, but with a noticeable curve, might suggest: —
A weak Pearson correlation but potentially a strong Spearman correlation.
10.
A correlation coefficient of 0.05 between hours of sleep and exam performance would indicate: —
A very weak positive linear relationship.
11.
A correlation coefficient of -0.95 suggests: —
A strong negative linear relationship.
12.
What does a Spearman's rho of -0.75 suggest? —
A strong negative monotonic relationship between the ranks of the variables.
13.
If Pearson's r is calculated on data that is not normally distributed, the p-value may be: —
Unreliable
14.
Which of the following statements about correlation is TRUE? —
Both B and C are true.
15.
A researcher finds a strong positive correlation between ice cream sales and drowning incidents. What is the most likely interpretation? —
There is a confounding variable (e.g., hot weather) influencing both.
16.
Which of the following is a graphical method to visualize the relationship between two variables? —
Scatterplot
17.
A monotonic relationship means that as one variable increases, the other variable: —
Either consistently increases or consistently decreases, but not necessarily at a constant rate.
18.
What is a key advantage of Spearman's correlation over Pearson's correlation? —
It does not require the data to be normally distributed.
19.
Spearman's rho is less affected by outliers than Pearson's r because: —
It transforms the data into ranks, which compresses the range of values.
20.
Spearman's rho is a measure of: —
Monotonic association.
21.
Which scenario would be most appropriate for using Spearman's rank correlation? —
Measuring the relationship between a doctor's rating of pain severity (ordinal) and a patient's reported pain level (ordinal).
22.
The formula for Spearman's rho involves calculating the difference between the ranks of paired observations and then: —
Summing the squares of these differences and applying a specific formula.
23.
Which type of correlation indicates that as one variable increases, the other variable also increases? —
Positive correlation
24.
Which type of variable is most suitable for Pearson correlation? —
Interval/Ratio
25.
Pearson's r is sensitive to which type of data? —
Interval or Ratio data
26.
Pearson's correlation coefficient is most appropriate when the relationship between variables is: —
Linear and interval/ratio.
27.
If two variables have a strong positive Pearson correlation, what can be inferred? —
As one variable increases, the other tends to increase linearly.
28.
Which of the following is NOT a type of correlation coefficient? —
Student's t
29.
Which correlation coefficient is generally considered more robust to non-normality and outliers? —
Spearman's rho
30.
Spearman's rank correlation coefficient is denoted by: —
rho (ρ)
31.
Pearson's correlation coefficient is also known as: —
Product-moment correlation coefficient
32.
What is the term for a correlation that appears to exist between two variables but is actually due to the influence of a third, unmeasured variable? —
Spurious correlation
33.
Which statistical test is used to calculate Pearson's correlation coefficient? —
None of the above (it's a formula)
34.
Spearman's correlation coefficient measures the strength and direction of the relationship between: —
The ranks of two variables.
35.
What does correlation analysis aim to measure? —
The strength and direction of the linear relationship between two variables.
36.
What is a common assumption for using Pearson's correlation coefficient? —
The variables must be normally distributed.
37.
Spearman's rho is a non-parametric measure, meaning it does not rely on assumptions about: —
The distribution of the data (e.g., normality).
38.
A correlation matrix displays: —
The pairwise correlation coefficients between multiple variables.
39.
Spearman's correlation works by calculating the Pearson correlation coefficient on: —
The ranks of the data for each variable.
40.
The primary difference between Pearson's r and Spearman's rho lies in: —
The type of relationship they measure (linear vs. monotonic).
41.
What does the coefficient of determination (r-squared) represent? —
The proportion of variance in one variable that is predictable from the other variable.
42.
The formula for Pearson's r involves: —
The product of deviations from the mean for each variable.
43.
Pearson's correlation coefficient is derived from: —
The covariance of the two variables divided by the product of their standard deviations.
44.
The null hypothesis for a correlation test typically states: —
There is no significant correlation between the variables.
45.
If a dataset has tied ranks, how is Spearman's rho typically calculated? —
The average rank is assigned to tied values.
46.
What is the primary purpose of hypothesis testing in correlation analysis? —
To determine if the observed correlation in the sample is likely to exist in the population.
47.
Spearman's correlation is used when: —
Data is ordinal or when the assumption of normality for Pearson's r is violated.
48.
When is it generally advisable to use Spearman's rho instead of Pearson's r? —
When there are outliers that might unduly influence Pearson's r, or when data is ordinal.
49.
When would you choose Kendall's tau correlation over Spearman's rho? —
When dealing with very large datasets and many tied ranks.