How do you find the variance when calculating statistics?

Finding variance involves a specific mathematical process that measures the spread of a set of values around their mean. The variance is computed by averaging the squared differences between each value in the dataset and the mean of the dataset. This method effectively quantifies how much the individual data points differ from the mean, which is the essence of understanding variability within the data.

To calculate variance:

1. Calculate the mean (average) of the data set.
2. Subtract the mean from each data point to find the deviation for each value.
3. Square each of these deviations to eliminate negative values and emphasize larger differences.
4. Average these squared deviations, which results in the variance.

This approach is crucial in statistics because it helps in various applications, such as assessing consistency or identifying anomalies in data sets. The other options do not accurately contribute to calculating variance. Counting values or adding the mean to each value does not address the distribution or spread of data; while taking the median relates to a different type of statistical measurement that describes the center of a data set but does not provide information about variance.