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  2. Hyperbolic secant distribution - Wikipedia

    en.wikipedia.org/wiki/Hyperbolic_secant_distribution

    Johnson et al. (1995) [1]: 147 places this distribution in the context of a class of generalized forms of the logistic distribution, but use a different parameterisation of the standard distribution compared to that here. Ding (2014) [2] shows three occurrences of the Hyperbolic secant distribution in statistical modeling and inference.

  3. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    The simplest case of a normal distribution is known as the standard normal distribution or unit normal distribution. This is a special case when μ = 0 {\textstyle \mu =0} and σ 2 = 1 {\textstyle \sigma ^{2}=1} , and it is described by this probability density function (or density): φ ( z ) = e − z 2 2 2 π . {\displaystyle \varphi (z ...

  4. Trigonometric tables - Wikipedia

    en.wikipedia.org/wiki/Trigonometric_tables

    A trigonometry table is essentially a reference chart that presents the values of sine, cosine, tangent, and other trigonometric functions for various angles. These angles are usually arranged across the top row of the table, while the different trigonometric functions are labeled in the first column on the left.

  5. Trigonometry - Wikipedia

    en.wikipedia.org/wiki/Trigonometry

    Abu al-Wafa had sine tables in 0.25° increments, to 8 decimal places of accuracy, and accurate tables of tangent values. [16] He also made important innovations in spherical trigonometry [17] [18] [19] The Persian polymath Nasir al-Din al-Tusi has been described as the creator of trigonometry as a mathematical discipline in its own right.

  6. Mathematical table - Wikipedia

    en.wikipedia.org/wiki/Mathematical_table

    The first tables of trigonometric functions known to be made were by Hipparchus (c.190 – c.120 BCE) and Menelaus (c.70–140 CE), but both have been lost. Along with the surviving table of Ptolemy (c. 90 – c.168 CE), they were all tables of chords and not of half-chords, that is, the sine function. [1]

  7. Standard normal table - Wikipedia

    en.wikipedia.org/wiki/Standard_normal_table

    It is used to find the probability that a statistic is observed below, above, or between values on the standard normal distribution, and by extension, any normal distribution. Since probability tables cannot be printed for every normal distribution, as there are an infinite variety of normal distributions, it is common practice to convert a ...

  8. Student's t-distribution - Wikipedia

    en.wikipedia.org/wiki/Student's_t-distribution

    As the number of degrees of freedom grows, the t distribution approaches the normal distribution with mean 0 and variance 1. For this reason is also known as the normality parameter. [3] The following images show the density of the t distribution for increasing values of .

  9. Gaussian function - Wikipedia

    en.wikipedia.org/wiki/Gaussian_function

    Specifically, if the mass-density at time t=0 is given by a Dirac delta, which essentially means that the mass is initially concentrated in a single point, then the mass-distribution at time t will be given by a Gaussian function, with the parameter a being linearly related to 1/ √ t and c being linearly related to √ t; this time-varying ...