The square of standard deviation is called variance. Variance is a statistical measure that quantifies the dispersion or spread of a set of data points. It tells us how far each number in the set is from the mean and, thus, from every other number in the set. To calculate the variance, we follow these steps: 1. Calculate the mean (average) of the data set. 2. Subtract the mean from each data point, then square the result. 3. Find the average of the squared differences. 4. This average is the variance.
The variance is useful because it gives us an idea of how spread out the data is from the mean. A higher variance indicates greater dispersion, while a lower variance indicates less dispersion. So, in summary, the correct answer is A) Variance.