What does standard deviation measure?

What does standard deviation measure?

• A. The average value of the data.
• B. A measure of the central tendency.
• C. The mean of the data.
• D. A measure of the spread of data values.

Answer: (D)

Standard deviation measures how spread out the data values are around the mean. It focuses on dispersion, not the center. A small standard deviation means most values are close to the average, while a large one shows data spread widely from the mean. For example, test scores tightly clustered near 75 have a small standard deviation; scores ranging from 40 to 110 have a large standard deviation. The standard deviation is derived from the average of the squared differences from the mean and then taking a square root, so it’s expressed in the same units as the data. In short, it quantifies the spread of the data values, not the central value itself.

Standard deviation measures how spread out the data values are around the mean. It focuses on dispersion, not the center. A small standard deviation means most values are close to the average, while a large one shows data spread widely from the mean. For example, test scores tightly clustered near 75 have a small standard deviation; scores ranging from 40 to 110 have a large standard deviation. The standard deviation is derived from the average of the squared differences from the mean and then taking a square root, so it’s expressed in the same units as the data. In short, it quantifies the spread of the data values, not the central value itself.