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  2. Basis of a matroid - Wikipedia

    en.wikipedia.org/wiki/Basis_of_a_matroid

    It has two bases, which are the sets {(0,1),(2,0)} , {(0,3),(2,0)}. These are the only independent sets that are maximal under inclusion. The basis has a specialized name in several specialized kinds of matroids: [1] In a graphic matroid, where the independent sets are the forests, the bases are called the spanning forests of the graph.

  3. Log-linear analysis - Wikipedia

    en.wikipedia.org/wiki/Log-linear_analysis

    To conduct chi-square analyses, one needs to break the model down into a 2 × 2 or 2 × 1 contingency table. [ 2 ] For example, if one is examining the relationship among four variables, and the model of best fit contained one of the three-way interactions, one would examine its simple two-way interactions at different levels of the third variable.

  4. Regression analysis - Wikipedia

    en.wikipedia.org/wiki/Regression_analysis

    For example, a researcher is building a linear regression model using a dataset that contains 1000 patients (). If the researcher decides that five observations are needed to precisely define a straight line ( m {\displaystyle m} ), then the maximum number of independent variables ( n {\displaystyle n} ) the model can support is 4, because

  5. Principal component regression - Wikipedia

    en.wikipedia.org/wiki/Principal_component_regression

    PCR is a form of reduced rank regression. [1] More specifically, PCR is used for estimating the unknown regression coefficients in a standard linear regression model. In PCR, instead of regressing the dependent variable on the explanatory variables directly, the principal components of the explanatory variables are used as regressors.

  6. Matroid - Wikipedia

    en.wikipedia.org/wiki/Matroid

    In combinatorics, a matroid / ˈ m eɪ t r ɔɪ d / is a structure that abstracts and generalizes the notion of linear independence in vector spaces.There are many equivalent ways to define a matroid axiomatically, the most significant being in terms of: independent sets; bases or circuits; rank functions; closure operators; and closed sets or flats.

  7. Parity-check matrix - Wikipedia

    en.wikipedia.org/wiki/Parity-check_matrix

    This means that a codeword c is in C if and only if the matrix-vector product Hc ⊤ = 0 (some authors [1] would write this in an equivalent form, cH ⊤ = 0.) The rows of a parity check matrix are the coefficients of the parity check equations. [2] That is, they show how linear combinations of certain digits (components) of each codeword equal ...

  8. Coefficient of multiple correlation - Wikipedia

    en.wikipedia.org/wiki/Coefficient_of_multiple...

    The coefficient of multiple correlation is known as the square root of the coefficient of determination, but under the particular assumptions that an intercept is included and that the best possible linear predictors are used, whereas the coefficient of determination is defined for more general cases, including those of nonlinear prediction and those in which the predicted values have not been ...

  9. Principal component analysis - Wikipedia

    en.wikipedia.org/wiki/Principal_component_analysis

    Dimensionality reduction may also be appropriate when the variables in a dataset are noisy. If each column of the dataset contains independent identically distributed Gaussian noise, then the columns of T will also contain similarly identically distributed Gaussian noise (such a distribution is invariant under the effects of the matrix W, which ...