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  2. 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.

  3. Sample size determination - Wikipedia

    en.wikipedia.org/wiki/Sample_size_determination

    The sample size is an important feature of any empirical study in which the goal is to make inferences about a population from a sample. In practice, the sample size used in a study is usually determined based on the cost, time, or convenience of collecting the data, and the need for it to offer sufficient statistical power. In complex studies ...

  4. Normal distribution - Wikipedia

    en.wikipedia.org/wiki/Normal_distribution

    This fact is known as the 68–95–99.7 (empirical) rule, or the 3-sigma rule. More precisely, the probability that a normal deviate lies in the range between ...

  5. Empirical statistical laws - Wikipedia

    en.wikipedia.org/wiki/Empirical_statistical_laws

    In business, the 80/20 rule says that 80% of your business comes from just 20% of your customers. [3] In software engineering, it is often said that 80% of the errors are caused by just 20% of the bugs. [4] 20% of the world creates roughly 80% of worldwide GDP. [5] 80% of healthcare expenses in the US are caused by 20% of the population. [6]

  6. Empirical distribution function - Wikipedia

    en.wikipedia.org/wiki/Empirical_distribution...

    In statistics, an empirical distribution function (commonly also called an empirical cumulative distribution function, eCDF) is the distribution function associated with the empirical measure of a sample. [1] This cumulative distribution function is a step function that jumps up by 1/n at each of the n data points. Its value at any specified ...

  7. Sample mean and covariance - Wikipedia

    en.wikipedia.org/wiki/Sample_mean_and_covariance

    The arithmetic mean of a population, or population mean, is often denoted μ. [2] The sample mean ¯ (the arithmetic mean of a sample of values drawn from the population) makes a good estimator of the population mean, as its expected value is equal to the population mean (that is, it is an unbiased estimator).

  8. Variance - Wikipedia

    en.wikipedia.org/wiki/Variance

    For a set of numbers {10, 15, 30, 45, 57, 52 63, 72, 81, 93, 102, 105}, if this set is the whole data population for some measurement, then variance is the population variance 932.743 as the sum of the squared deviations about the mean of this set, divided by 12 as the number of the set members.

  9. Empirical risk minimization - Wikipedia

    en.wikipedia.org/wiki/Empirical_risk_minimization

    Empirical risk minimization for a classification problem with a 0-1 loss function is known to be an NP-hard problem even for a relatively simple class of functions such as linear classifiers. [5] Nevertheless, it can be solved efficiently when the minimal empirical risk is zero, i.e., data is linearly separable .