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  2. Heart rate variability - Wikipedia

    en.wikipedia.org/wiki/Heart_rate_variability

    Heart rate variability visualized with R-R interval changes Electrocardiogram (ECG) recording of a canine heart that illustrates beat-to-beat variability in R–R interval (top) and heart rate (bottom). Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the ...

  3. Gamma distribution - Wikipedia

    en.wikipedia.org/wiki/Gamma_distribution

    Phylogenetic analyzes that use the gamma distribution to model rate variation estimate a single parameter from the data because they limit consideration to distributions where α = λ. This parameterization means that the mean of this distribution is 1 and the variance is 1/α. Maximum likelihood and Bayesian methods typically use a discrete ...

  4. Variance - Wikipedia

    en.wikipedia.org/wiki/Variance

    The general formula for variance decomposition or the law of total variance is: If and are two random variables, and the ...

  5. Exponential distribution - Wikipedia

    en.wikipedia.org/wiki/Exponential_distribution

    In probability theory and statistics, the exponential distribution or negative exponential distribution is the probability distribution of the distance between events in a Poisson point process, i.e., a process in which events occur continuously and independently at a constant average rate; the distance parameter could be any meaningful mono-dimensional measure of the process, such as time ...

  6. Coefficient of variation - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_variation

    This follows from the fact that the variance and mean are independent of the ordering of x. Scale invariance: c v (x) = c v (αx) where α is a real number. [22] Population independence – If {x,x} is the list x appended to itself, then c v ({x,x}) = c v (x). This follows from the fact that the variance and mean both obey this principle.

  7. Statistical dispersion - Wikipedia

    en.wikipedia.org/wiki/Statistical_dispersion

    Variance-to-mean ratio – mostly used for count data when the term coefficient of dispersion is used and when this ratio is dimensionless, as count data are themselves dimensionless, not otherwise. Some measures of dispersion have specialized purposes. The Allan variance can be used for applications where the noise disrupts convergence. [2]

  8. Root mean square deviation - Wikipedia

    en.wikipedia.org/wiki/Root_mean_square_deviation

    For an unbiased estimator, the RMSD is the square root of the variance, known as the standard deviation. Samples ... , the formula becomes = = (,,). ...

  9. Algorithms for calculating variance - Wikipedia

    en.wikipedia.org/wiki/Algorithms_for_calculating...

    This algorithm can easily be adapted to compute the variance of a finite population: simply divide by n instead of n − 1 on the last line.. Because SumSq and (Sum×Sum)/n can be very similar numbers, cancellation can lead to the precision of the result to be much less than the inherent precision of the floating-point arithmetic used to perform the computation.