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.