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  2. Z-test - Wikipedia

    en.wikipedia.org/wiki/Z-test

    To calculate the standardized statistic = (¯), we need to either know or have an approximate value for σ 2, from which we can calculate =. In some applications, σ 2 is known, but this is uncommon. If the sample size is moderate or large, we can substitute the sample variance for σ 2 , giving a plug-in test.

  3. Riemann–Siegel formula - Wikipedia

    en.wikipedia.org/wiki/Riemann–Siegel_formula

    It is often used to compute values of the Riemann–Siegel formula, sometimes in combination with the Odlyzko–Schönhage algorithm which speeds it up considerably. When used along the critical line, it is often useful to use it in a form where it becomes a formula for the Z function.

  4. Standard normal table - Wikipedia

    en.wikipedia.org/wiki/Standard_normal_table

    Z tables use at least three different conventions: Cumulative from mean gives a probability that a statistic is between 0 (mean) and Z. Example: Prob(0 ≤ Z ≤ 0.69) = 0.2549. Cumulative gives a probability that a statistic is less than Z. This equates to the area of the distribution below Z. Example: Prob(Z ≤ 0.69) = 0.7549. Complementary ...

  5. Z-factor - Wikipedia

    en.wikipedia.org/wiki/Z-factor

    The Z-factor defines a characteristic parameter of the capability of hit identification for each given assay. The following categorization of HTS assay quality by the value of the Z-Factor is a modification of Table 1 shown in Zhang et al. (1999); [2] note that the Z-factor cannot exceed one.

  6. Stirling's approximation - Wikipedia

    en.wikipedia.org/wiki/Stirling's_approximation

    The formula was first discovered by Abraham de Moivre [2] in the form ! [] +. De Moivre gave an approximate rational-number expression for the natural logarithm of the constant. Stirling's contribution consisted of showing that the constant is precisely 2 π {\displaystyle {\sqrt {2\pi }}} .

  7. The rule of 25 for retirement: What it means and how to ... - AOL

    www.aol.com/finance/rule-25-retirement-means...

    Let’s say you plan to collect $20,000 in Social Security benefits each year. Subtract that from your annual retirement expenses (40,000 – 20,0000 = $20,000). Finally, apply the rule of 25.

  8. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    The general form of its probability density function is [2] [3] = (). The parameter μ {\textstyle \mu } is the mean or expectation of the distribution (and also its median and mode ), while the parameter σ 2 {\textstyle \sigma ^{2}} is the variance .

  9. Prenex normal form - Wikipedia

    en.wikipedia.org/wiki/Prenex_normal_form

    Tarski's axioms for geometry is a logical system whose sentences can all be written in universal–existential form, a special case of the prenex normal form that has every universal quantifier preceding any existential quantifier, so that all sentences can be rewritten in the form … , where is a sentence that does not contain any quantifier.