Standard deviation dispersion measure – UGC NET Question

Standard deviation quantifies the spread of scores around the mean by taking the square root of the average of squared deviations. A larger standard deviation indicates that scores are more widely dispersed, while a smaller one shows they cluster closely around the mean. It is widely used because it relates directly to variance and plays a central role in many statistical procedures. Therefore, the measure described in the stem is correctly called the standard deviation.

Option A:
Standard deviation provides a more informative picture of variability than the range because it considers all data points, not just extremes. It is also compatible with normal distribution theory and confidence intervals, making it a fundamental descriptive statistic. These properties align with the stem’s focus on average deviation from the mean, so this option is correct.

Option B:
The mean is a measure of central tendency, representing the average score, and does not describe how far scores typically lie from that average.

Option C:
The mode is the most frequently occurring value in a distribution and gives no information about overall dispersion.

Option D:
The range is the difference between the highest and lowest scores and is sensitive only to extreme values, not to the overall spread, so it does not match the stem.