Answer
The term correlation is used for the variable that is quantitative, and the term association is used for the variable that is qualitative.
Work Step by Step
The variable that provides the numerical values is called the quantitative variable, and the variable that is classified into a category or an attribute or a quality is called the qualitative variable. Correlation provides a numerical value of the data and it can be calculated by using the following formula:
\[r=\frac{\sum{\left( \frac{{{x}_{i}}-\bar{x}}{{{s}_{x}}} \right)}\left( \frac{{{y}_{i}}-\bar{y}}{{{s}_{y}}} \right)}{n-1}\]
Here, the correlation coefficient is denoted by r.
To compute the correlation coefficient, the sample mean and the sample standard deviation are needed. The values of the mean and the standard deviation cannot be computed for the categorical variables. So, it’s better to use the term “association” instead of the term “correlation.”
