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  2. Mann–Whitney U test - Wikipedia

    en.wikipedia.org/wiki/Mann–Whitney_U_test

    The Mann–Whitney test (also called the Mann–Whitney–Wilcoxon (MWW/MWU), Wilcoxon rank-sum test, or Wilcoxon–Mann–Whitney test) is a nonparametric statistical test of the null hypothesis that, for randomly selected values X and Y from two populations, the probability of X being greater than Y is equal to the probability of Y being greater than X.

  3. Rank (linear algebra) - Wikipedia

    en.wikipedia.org/wiki/Rank_(linear_algebra)

    A matrix is said to have full rank if its rank equals the largest possible for a matrix of the same dimensions, which is the lesser of the number of rows and columns. A matrix is said to be rank-deficient if it does not have full rank. The rank deficiency of a matrix is the difference between the lesser of the number of rows and columns, and ...

  4. Wilcoxon signed-rank test - Wikipedia

    en.wikipedia.org/wiki/Wilcoxon_signed-rank_test

    The modified signed-rank sum , the modified positive-rank sum +, and the modified negative-rank sum are defined analogously to , +, and but with the modified ranks in place of the ordinary ranks. The probability that the sum of two independent F {\displaystyle F} -distributed random variables is positive can be estimated as 2 T 0 + / ( n ( n ...

  5. Rank correlation - Wikipedia

    en.wikipedia.org/wiki/Rank_correlation

    Dave Kerby (2014) recommended the rank-biserial as the measure to introduce students to rank correlation, because the general logic can be explained at an introductory level. The rank-biserial is the correlation used with the Mann–Whitney U test, a method commonly covered in introductory college courses on statistics. The data for this test ...

  6. Matrix norm - Wikipedia

    en.wikipedia.org/wiki/Matrix_norm

    Suppose a vector norm ‖ ‖ on and a vector norm ‖ ‖ on are given. Any matrix A induces a linear operator from to with respect to the standard basis, and one defines the corresponding induced norm or operator norm or subordinate norm on the space of all matrices as follows: ‖ ‖, = {‖ ‖: ‖ ‖ =} = {‖ ‖ ‖ ‖:} . where denotes the supremum.

  7. Rank of a group - Wikipedia

    en.wikipedia.org/wiki/Rank_of_a_group

    [18] [19] The notion of co-rank is related to the notion of a cut number for 3-manifolds. [20] If p is a prime number, then the p-rank of G is the largest rank of an elementary abelian p-subgroup. [21] The sectional p-rank is the largest rank of an elementary abelian p-section (quotient of a subgroup).

  8. Ranking - Wikipedia

    en.wikipedia.org/wiki/Ranking

    In language, the status of an item (usually through what is known as "downranking" or "rank-shifting") in relation to the uppermost rank in a clause; for example, in the sentence "I want to eat the cake you made today", "eat" is on the uppermost rank, but "made" is downranked as part of the nominal group "the cake you made today"; this nominal ...

  9. Projection matrix - Wikipedia

    en.wikipedia.org/wiki/Projection_matrix

    For linear models, the trace of the projection matrix is equal to the rank of , which is the number of independent parameters of the linear model. [8] For other models such as LOESS that are still linear in the observations y {\displaystyle \mathbf {y} } , the projection matrix can be used to define the effective degrees of freedom of the model.