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  2. Log-normal distribution - Wikipedia

    en.wikipedia.org/wiki/Log-normal_distribution

    The file size distribution of publicly available audio and video data files follows a log-normal distribution over five orders of magnitude. [92] File sizes of 140 million files on personal computers running the Windows OS, collected in 1999. [93] [62] Sizes of text-based emails (1990s) and multimedia-based emails (2000s). [62]

  3. Normalization (statistics) - Wikipedia

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

    This is also called unity-based normalization. This can be generalized to restrict the range of values in the dataset between any arbitrary points a {\displaystyle a} and b {\displaystyle b} , using for example X ′ = a + ( X − X min ) ( b − a ) X max − X min {\displaystyle X'=a+{\frac {\left(X-X_{\min }\right)\left(b-a\right)}{X_{\max ...

  4. Data transformation (statistics) - Wikipedia

    en.wikipedia.org/wiki/Data_transformation...

    The upper plot uses raw data. In the lower plot, both the area and population data have been transformed using the logarithm function. In statistics , data transformation is the application of a deterministic mathematical function to each point in a data set—that is, each data point z i is replaced with the transformed value y i = f ( z i ...

  5. Database normalization - Wikipedia

    en.wikipedia.org/wiki/Database_normalization

    Database normalization is the process of structuring a relational database accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. It was first proposed by British computer scientist Edgar F. Codd as part of his relational model .

  6. Quantile normalization - Wikipedia

    en.wikipedia.org/wiki/Quantile_normalization

    In statistics, quantile normalization is a technique for making two distributions identical in statistical properties. To quantile-normalize a test distribution to a reference distribution of the same length, sort the test distribution and sort the reference distribution.

  7. Logit - Wikipedia

    en.wikipedia.org/wiki/Logit

    If p is a probability, then p/(1 − p) is the corresponding odds; the logit of the probability is the logarithm of the odds, i.e.: ⁡ = ⁡ = ⁡ ⁡ = ⁡ = ⁡ (). The base of the logarithm function used is of little importance in the present article, as long as it is greater than 1, but the natural logarithm with base e is the one most often used.

  8. Raw data - Wikipedia

    en.wikipedia.org/wiki/Raw_data

    Raw data (sometimes colloquially called "sources" data or "eggy" data, the latter a reference to the data being "uncooked", that is, "unprocessed", like a raw egg) are the data input to processing. A distinction is made between data and information , to the effect that information is the end product of data processing.

  9. Standardized moment - Wikipedia

    en.wikipedia.org/wiki/Standardized_moment

    Let X be a random variable with a probability distribution P and mean value = [] (i.e. the first raw moment or moment about zero), the operator E denoting the expected value of X. Then the standardized moment of degree k is μ k σ k , {\displaystyle {\frac {\mu _{k}}{\sigma ^{k}}},} [ 2 ] that is, the ratio of the k th moment about the mean