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  2. Variance - Wikipedia

    en.wikipedia.org/wiki/Variance

    A frequency distribution is constructed. ... This definition encompasses random variables that are generated by ... the population variance of a finite population of ...

  3. Frequency (statistics) - Wikipedia

    en.wikipedia.org/wiki/Frequency_(statistics)

    A frequency distribution shows a summarized grouping of data divided into mutually exclusive classes and the number of occurrences in a class. It is a way of showing unorganized data notably to show results of an election, income of people for a certain region, sales of a product within a certain period, student loan amounts of graduates, etc.

  4. Statistical dispersion - Wikipedia

    en.wikipedia.org/wiki/Statistical_dispersion

    Some measures of dispersion have specialized purposes. The Allan variance can be used for applications where the noise disrupts convergence. [2] The Hadamard variance can be used to counteract linear frequency drift sensitivity. [3] For categorical variables, it is less common to measure dispersion by a single number; see qualitative variation.

  5. Allan variance - Wikipedia

    en.wikipedia.org/wiki/Allan_variance

    The Allan variance depends on the time period used between samples, therefore, it is a function of the sample period, commonly denoted as τ, likewise the distribution being measured, and is displayed as a graph rather than a single number. A low Allan variance is a characteristic of a clock with good stability over the measured period.

  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. Heart rate variability - Wikipedia

    en.wikipedia.org/wiki/Heart_rate_variability

    The bands are typically high frequency (HF) from 0.15 to 0.4 Hz, low frequency (LF) from 0.04 to 0.15 Hz, and the very low frequency (VLF) from 0.0033 to 0.04 Hz. [50] HF power reflects stimulation by the parasympathetic nervous system (PNS), whereas LF power reflects stimulation by both the sympathetic nervous system (SNS) and the PNS. [ 50 ]

  8. Signal-to-noise ratio - Wikipedia

    en.wikipedia.org/wiki/Signal-to-noise_ratio

    One definition of signal-to-noise ratio is the ratio of the power of a signal ... the denominator is its variance, ... the frequency and the receiver.

  9. Variance function - Wikipedia

    en.wikipedia.org/wiki/Variance_function

    In statistics, the variance function is a smooth function that depicts the variance of a random quantity as a function of its mean.