Which statistic is the square root of the variance?

Which statistic is the square root of the variance?

• A. Range
• B. Mean
• C. Standard Deviation (SD)
• D. Mode

Answer: (C)

The standard deviation is the square root of the variance. Variance measures how far data points typically lie from the mean by averaging the squared deviations. Taking the square root brings that measure back to the original units of the data, giving a sense of typical distance from the mean. This makes the standard deviation a natural, interpretable descriptor of spread. The other options don’t perform this role: range only captures the span between the extremes, the mean describes center, and the mode identifies the most frequent value.

The standard deviation is the square root of the variance. Variance measures how far data points typically lie from the mean by averaging the squared deviations. Taking the square root brings that measure back to the original units of the data, giving a sense of typical distance from the mean. This makes the standard deviation a natural, interpretable descriptor of spread. The other options don’t perform this role: range only captures the span between the extremes, the mean describes center, and the mode identifies the most frequent value.