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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. Standard normal table - Wikipedia

    en.wikipedia.org/wiki/Standard_normal_table

    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. That is Prob(Z ≥ 0.69) = 1 − Prob(Z ≤ 0.69) or Prob(Z ≥ 0.69) = 1 − 0.7549 ...

  4. 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.

  5. Normal score - Wikipedia

    en.wikipedia.org/wiki/Normal_score

    The term normal score is used with two different meanings in statistics. One of them relates to creating a single value which can be treated as if it had arisen from a standard normal distribution (zero mean, unit variance). The second one relates to assigning alternative values to data points within a dataset, with the broad intention of ...

  6. Z-factor - Wikipedia

    en.wikipedia.org/wiki/Z-factor

    The Z-factor is a measure of statistical effect size. It has been proposed for use in high-throughput screening (HTS), where it is also known as Z-prime, [ 1 ] to judge whether the response in a particular assay is large enough to warrant further attention.

  7. 97.5th percentile point - Wikipedia

    en.wikipedia.org/wiki/97.5th_percentile_point

    In probability and statistics, the 97.5th percentile point of the standard normal distribution is a number commonly used for statistical calculations. The approximate value of this number is 1.96 , meaning that 95% of the area under a normal curve lies within approximately 1.96 standard deviations of the mean .

  8. 68–95–99.7 rule - Wikipedia

    en.wikipedia.org/wiki/68–95–99.7_rule

    In statistics, the 68–95–99.7 rule, also known as the empirical rule, and sometimes abbreviated 3sr, is a shorthand used to remember the percentage of values that lie within an interval estimate in a normal distribution: approximately 68%, 95%, and 99.7% of the values lie within one, two, and three standard deviations of the mean, respectively.

  9. Probability density function - Wikipedia

    en.wikipedia.org/wiki/Probability_density_function

    To compute the quotient Y = U/V of two independent random variables U and V, define the following transformation: = / = Then, the joint density p(y,z) can be computed by a change of variables from U,V to Y,Z, and Y can be derived by marginalizing out Z from the joint density.