A. The Pearson correlation is used to score variables
B. The Spearman correlation is used for nominal variable
C. The numerical size of the correlation ranges from -0.1 to +0.1
D. The Spearman correlation is used for internal variable
Choose the correct answer from the options given below:
Correlation Coefficient Explanation
Let's analyze each statement regarding the correlation coefficient:
- Statement A: The Pearson correlation is used to score variables. This statement is considered correct in the context of the question. The Pearson correlation coefficient ($r$) measures the strength and direction of a linear relationship between two *continuous* variables (interval or ratio scale). These are often variables that can be "scored".
- Statement B: The Spearman correlation is used for nominal variable. This is incorrect. The Spearman rank-order correlation coefficient ($\rho$) is used for measuring the strength and direction of association between two *ranked* or *ordinal* variables. Nominal variables represent categories and require different types of analysis.
- Statement C: The numerical size of the correlation ranges from -0.1 to +0.1. This is incorrect. The numerical size (absolute value) of any standard correlation coefficient, including Pearson and Spearman, ranges from $0.0$ to $1.0$. The actual values range from $-1.0$ (perfect negative correlation) to $+1.0$ (perfect positive correlation).
- Statement D: The Spearman correlation is used for internal variable. This statement is unclear as "internal variable" is not standard statistical terminology. However, Spearman correlation is specifically designed for ordinal or ranked data, not generally for any unspecified "internal" variable type. Since statement A is the best fit and the correct answer is given as 'A only', this statement is considered incorrect.
Conclusion
Based on the analysis, only statement A holds true within the typical understanding of correlation coefficients and their applications, assuming "score variables" refers to continuous or interval/ratio scale data suitable for Pearson correlation.
Therefore, the correct option is A only.
Important Questions from Correlation Analysis - Teaching
- Arrange the following in terms of increasing order of the minimum number of variables required for their
computation:
A. Mean
B. First order correlation
C. Correlation coefficient
D. Second order correlation
Choose the correct answer from the options given below: - Which of the following correlation coefficient represents the variables with the weakest degree of relationship?
- Match List I with List IIChoose the correct answer from the options given below:
LIST I LIST II A. An inferential test used to determine effect size for a chi-square test; the correlation used when both measured variables are dichotomous and nominal I. Point-biserial correlation coefficient B. The correlation used when one of its variables is measured on a dichotomous nominal scale and the other is measured on an interval or ratio scale II. Regression analysis C. A procedure that allows to predict an individual's score on one variable based on knowing one or more variables III. Partial correlation D. A correlational technique that involves measuring three variables and then statistically removing the effect of the third variable from the correlation of the remaining two variables IV. Phi-coefficient - In a study, a researcher wants to eliminate the effect of one variable in a bid to find out the pure relationship between two variables of his/her interest. He/She should be advised to use which of the following methods of computing coefficient of correlation ?
Assertion (A) : There is a positive co-relation between literacy and primary education.
Reason (R) : It has been found that total literate districts have shown increase in enrolment at primary level.
Codes :
