Below are two statements:
Statement I: Spearman's rho (ρ) is commonly used to measure the strength and direction of the association between two ordinal variables.
Statement II: Pearson's correlation coefficient 'r' is quite useful when the relationship between two variables is curvilinear.
Based on the above statements, select the most appropriate answer from the options given below:

Correct option is C

The correct answer is (c) Statement I is correct, but Statement II is incorrect.
 Statement I: Correct. Spearman's rho (ρ) is indeed commonly used to measure the strength and direction of the association between two ordinal variables. Spearman's rank correlation coefficient is a non-parametric measure of correlation, meaning it does not assume a normal distribution of the variables. It assesses how well the relationship between two variables can be described using a monotonic function.
 Statement II: Incorrect. Pearson's correlation coefficient 'r' is used to measure the strength and direction of the linear relationship between two continuous variables. It is not suitable for identifying curvilinear relationships. If the relationship between the variables is curvilinear, Pearson's 'r' may not accurately reflect the strength of the relationship. Other methods or types of analysis are better suited for curvilinear relationships, such as polynomial regression or Spearman's rho for ordinal data, which can capture nonlinear trends if the relationship is monotonic.