1Cademy - Statistical Standard Deviation Formula

Learn Before

Standard Deviation

Formula

Statistical Standard Deviation Formula

The standard deviation ( $SD$ ) for describing the variability of a sample is computed by finding the difference between each score ( $X$ ) and the mean ( $M$ ), squaring each difference, finding the mean of these squared values, and taking the square root. The formula is: $SD = \sqrt{\frac{\sum (X-M)^2}{N}}$ , where $N$ is the total number of scores.