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  2. 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 ...

  3. Range query (computer science) - Wikipedia

    en.wikipedia.org/wiki/Range_query_(computer_science)

    Given a function that accepts an array, a range query (,) on an array = [,..,] takes two indices and and returns the result of when applied to the subarray [, …,].For example, for a function that returns the sum of all values in an array, the range query ⁡ (,) returns the sum of all values in the range [,].

  4. Raising and lowering indices - Wikipedia

    en.wikipedia.org/wiki/Raising_and_lowering_indices

    In finite dimension, the dual space has equal dimension to , so non-degeneracy is enough to conclude the map is a linear isomorphism. If ϕ {\displaystyle \phi } is a structure on the vector space sometimes call this the canonical isomorphism V → V ∗ {\displaystyle V\rightarrow V^{*}} .

  5. Correlation - Wikipedia

    en.wikipedia.org/wiki/Correlation

    The correlation reflects the noisiness and direction of a linear relationship (top row), but not the slope of that relationship (middle), nor many aspects of nonlinear relationships (bottom). N.B.: the figure in the center has a slope of 0 but in that case, the correlation coefficient is undefined because the variance of Y is zero.

  6. Pivot table - Wikipedia

    en.wikipedia.org/wiki/Pivot_table

    Row labels are used to apply a filter to one or more rows that have to be shown in the pivot table. For instance, if the "Salesperson" field is dragged on this area then the other output table constructed will have values from the column "Salesperson", i.e., one will have a number of rows equal to the number of "Sales Person". There will also ...

  7. Loss functions for classification - Wikipedia

    en.wikipedia.org/wiki/Loss_functions_for...

    Given the binary nature of classification, a natural selection for a loss function (assuming equal cost for false positives and false negatives) would be the 0-1 loss function (0–1 indicator function), which takes the value of 0 if the predicted classification equals that of the true class or a 1 if the predicted classification does not match ...

  8. Data analysis - Wikipedia

    en.wikipedia.org/wiki/Data_analysis

    By splitting the data into multiple parts, we can check if an analysis (like a fitted model) based on one part of the data generalizes to another part of the data as well. [144] Cross-validation is generally inappropriate, though, if there are correlations within the data, e.g. with panel data . [ 145 ]

  9. k-means clustering - Wikipedia

    en.wikipedia.org/wiki/K-means_clustering

    Davies–Bouldin index: The Davies-Bouldin index is a measure of the how much separation there is between clusters. [32] Lower values of the Davies-Bouldin index indicate a model with better separation. Calinski-Harabasz index: This Index evaluates clusters based on their compactness and separation. The index is calculated using the ratio of ...