Standard Deviation
- Standard deviation is the square root of the variance, i.e. the square root of the mean of the squares of the deviations from the mean value of a vibrating quantity. The square of the standard deviation is the variance. An expression of the so-called "second moment," which describes the "dispersion" or variability around the mean.
- In noise data, the standard deviation should be approximately the same as the rms.
- for the data series: x1, x2, x3,....,xn the standard deviation of a sample, σ is:
- In noise data, the standard deviation should be approximately the same as the rms.
- The standard deviation of the entire population, σp
| 3σ | Represents about the same likelihood of tossing a coin and getting more than eight heads in a row. |
| 5σ | The level of certainty required in Particle Physics for a "discovery". |
| 5σ | Corresponds to tossing a coin and getting more than 20 heads in a row. |
See also: Average Deviation, Mean, Normal Distribution, Relative Standard Deviation, Standard Error, Statistic, Variance.
Subjects: Statistics