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  2. Stirling's approximation - Wikipedia

    en.wikipedia.org/wiki/Stirling's_approximation

    In mathematics, Stirling's approximation (or Stirling's formula) is an asymptotic approximation for factorials. It is a good approximation, leading to accurate results even for small values of n {\displaystyle n} .

  3. Scott's rule - Wikipedia

    en.wikipedia.org/wiki/Scott's_Rule

    Scott's rule is a method to select the number of bins in a histogram. [1] Scott's rule is widely employed in data analysis software including R, [2] Python [3] and Microsoft Excel where it is the default bin selection method. [4]

  4. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    Newton's method is ideal to solve this problem because the first derivative of (), which is an integral of the normal standard distribution, is the normal standard distribution, and is readily available to use in the Newton's method solution.

  5. Standard normal table - Wikipedia

    en.wikipedia.org/wiki/Standard_normal_table

    Example: Prob(Z ≤ 0.69) = 0.7549. Complementary cumulative gives a probability that a statistic is greater than Z. This equates to the area of the distribution above Z. Example: Find Prob(Z ≥ 0.69). Since this is the portion of the area above Z, the proportion that is greater than Z is found by subtracting Z from 1.

  6. 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.

  7. Standard score - Wikipedia

    en.wikipedia.org/wiki/Standard_score

    Comparison of the various grading methods in a normal distribution, including: standard deviations, cumulative percentages, percentile equivalents, z-scores, T-scores. In statistics, the standard score is the number of standard deviations by which the value of a raw score (i.e., an observed value or data point) is above or below the mean value of what is being observed or measured.

  8. 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.

  9. 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.