Now we get to the most frequently used measure of variability, the standard deviation. Just think about what the term implies—it’s a deviation from something (guess what?) that has been standardized. Actually, the standard deviation (sometimes abbreviated as SD, sometimes s) represents the average amount of variability in a set of scores. In practical terms, it’s the average distance of each score from the mean. The larger the standard deviation, the larger the average distance each data point is from
