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  2. Pivot table - Wikipedia

    en.wikipedia.org/wiki/Pivot_table

    A pivot table is a table of values which are aggregations of groups of individual values from a more extensive table (such as from a database, spreadsheet, or business intelligence program) within one or more discrete categories. The aggregations or summaries of the groups of the individual terms might include sums, averages, counts, or other ...

  3. Pivotal quantity - Wikipedia

    en.wikipedia.org/wiki/Pivotal_quantity

    The function (,) is the Student's t-statistic for a new value , to be drawn from the same population as the already observed set of values . Using x = μ {\displaystyle x=\mu } the function g ( μ , X ) {\displaystyle g(\mu ,X)} becomes a pivotal quantity, which is also distributed by the Student's t-distribution with ν = n − 1 ...

  4. Algorithms for calculating variance - Wikipedia

    en.wikipedia.org/wiki/Algorithms_for_calculating...

    Algorithms for calculating variance play a major role in computational statistics.A key difficulty in the design of good algorithms for this problem is that formulas for the variance may involve sums of squares, which can lead to numerical instability as well as to arithmetic overflow when dealing with large values.

  5. Lift (data mining) - Wikipedia

    en.wikipedia.org/wiki/Lift_(data_mining)

    because these are simply the most common patterns found in the data. A simple review of the above table should make these rules obvious. The support for Rule 1 is 3/7 because that is the number of items in the dataset in which the antecedent is A and the consequent 0. The support for Rule 2 is 2/7 because two of the seven records meet the ...

  6. Pivot element - Wikipedia

    en.wikipedia.org/wiki/Pivot_element

    The pivot or pivot element is the element of a matrix, or an array, which is selected first by an algorithm (e.g. Gaussian elimination, simplex algorithm, etc.), to do certain calculations. In the case of matrix algorithms, a pivot entry is usually required to be at least distinct from zero, and often distant from it; in this case finding this ...

  7. Median of medians - Wikipedia

    en.wikipedia.org/wiki/Median_of_medians

    The median-calculating recursive call does not exceed worst-case linear behavior because the list of medians has size , while the other recursive call recurses on at most 70% of the list. Let T ( n ) {\displaystyle T(n)} be the time it takes to run a median-of-medians Quickselect algorithm on an array of size n {\displaystyle n} .

  8. Selection algorithm - Wikipedia

    en.wikipedia.org/wiki/Selection_algorithm

    As a baseline algorithm, selection of the th smallest value in a collection of values can be performed by the following two steps: . Sort the collection; If the output of the sorting algorithm is an array, retrieve its th element; otherwise, scan the sorted sequence to find the th element.

  9. Spearman's rank correlation coefficient - Wikipedia

    en.wikipedia.org/wiki/Spearman's_rank_correlation...

    Python has many different implementations of the spearman correlation statistic: it can be computed with the spearmanr function of the scipy.stats module, as well as with the DataFrame.corr(method='spearman') method from the pandas library, and the corr(x, y, method='spearman') function from the statistical package pingouin.