Standard deviation is a statistic measuring the dispersion of a dataset relative to its mean. It is calculated as the square root of the variance. Learn how it's used.

The standard deviation formula for a sample is almost the same as the formula for a population, except you subtract N by 1 in the denominator, so it's: σ = √(Σ(xi - μ)² / N-1).

Another way to interpret the normal distribution is to say that the probability of Apple’s return (at a range of -1.83 percent and 1.99 percent) falling within -1 and 1 standard deviation from ...

Standard deviations are important here because the shape of a normal curve is determined by its mean and standard deviation. The mean tells you where the middle, highest part of the curve should go.

The formula for pooled standard deviation. In the formula above, n is the sample size of the group, S squared the group ...

Standard deviation is a measure of how far away individual measurements tend to be from the mean value of a data set. The standard deviation of company A's employees is 1, while the standard ...

The residual standard deviation describes the difference in standard deviations of observed values vs. predicted values in a regression analysis.

Use Excel to calculate daily returns and standard deviation to gauge stock volatility. Annualize volatility by multiplying daily standard deviation by the square root of 252. Remember, standard ...