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  2. Central limit theorem - Wikipedia

    en.wikipedia.org/wiki/Central_limit_theorem

    Many central limit theorems provide conditions such that S n / √ Var(S n) converges in distribution to N(0,1) (the normal distribution with mean 0, variance 1) as n → ∞. In some cases, it is possible to find a constant σ 2 and function f(n) such that S n /(σ √ n⋅f ( n ) ) converges in distribution to N (0,1) as n → ∞ .

  3. 97.5th percentile point - Wikipedia

    en.wikipedia.org/wiki/97.5th_percentile_point

    "The value for which P = .05, or 1 in 20, is 1.96 or nearly 2; it is convenient to take this point as a limit in judging whether a deviation is to be considered significant or not." [11] In Table 1 of the same work, he gave the more precise value 1.959964. [12] In 1970, the value truncated to 20 decimal places was calculated to be

  4. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    [4] [5] Their importance is partly due to the central limit theorem. It states that, under some conditions, the average of many samples (observations) of a random variable with finite mean and variance is itself a random variable—whose distribution converges to a normal distribution as the number of samples increases.

  5. Central limit theorem for directional statistics - Wikipedia

    en.wikipedia.org/wiki/Central_limit_theorem_for...

    The means and variances of directional quantities are all finite, so that the central limit theorem may be applied to the particular case of directional statistics. [2] This article will deal only with unit vectors in 2-dimensional space (R 2) but the method described can be extended to the general case.

  6. Confidence interval - Wikipedia

    en.wikipedia.org/wiki/Confidence_interval

    The central limit theorem is a refinement of the law of large numbers. ... Suppose we wanted to calculate a 95% confidence interval for ...

  7. Standard error - Wikipedia

    en.wikipedia.org/wiki/Standard_error

    when the probability distribution is unknown, Chebyshev's or the Vysochanskiï–Petunin inequalities can be used to calculate a conservative confidence interval; and; as the sample size tends to infinity the central limit theorem guarantees that the sampling distribution of the mean is asymptotically normal.

  8. Chi-squared distribution - Wikipedia

    en.wikipedia.org/wiki/Chi-squared_distribution

    By the central limit theorem, because the chi-squared distribution is the sum of independent random variables with finite mean and variance, it converges to a normal distribution for large . For many practical purposes, for k > 50 {\displaystyle k>50} the distribution is sufficiently close to a normal distribution , so the difference is ...

  9. Central tendency - Wikipedia

    en.wikipedia.org/wiki/Central_tendency

    In statistics, a central tendency (or measure of central tendency) is a central or typical value for a probability distribution. [1] Colloquially, measures of central tendency are often called averages. The term central tendency dates from the late 1920s. [2] The most common measures of central tendency are the arithmetic mean, the median, and ...