Counselor Education Comprehensive Exam (CECE) Practice Exam

What is the most frequently reported indicator of variability for interval or ratio data?

1. Range

2. Standard deviation

3. Variance

4. Sum of squares

The correct answer is: Standard deviation

The most frequently reported indicator of variability for interval or ratio data is the standard deviation. Standard deviation provides a measure of the dispersion of a set of data points around their mean. It quantifies how much individual data points differ from the mean, offering meaningful insights into the data's spread. Standard deviation is particularly useful because it is expressed in the same units as the original data, making it straightforward to interpret. This characteristic allows practitioners to compare variability across different datasets directly. Additionally, it captures the effects of every value in the dataset, providing a comprehensive understanding of variability. In contrast, while the range measures the difference between the highest and lowest values, it only gives a limited view of variability as it does not consider how values are distributed between them. Variance, although related to standard deviation, is expressed in squared units, making its interpretation less intuitive for practical applications. The sum of squares is a component in calculating variance and standard deviation, but it does not serve as a direct measure of variability itself. Therefore, among these options, standard deviation emerges as the most appropriate and frequently utilized measure of variability for interval or ratio data.