Asymptotic normality of MRPP statistics from invariance principles of u-statistics |
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Authors: | Federico J O'Reilly Paul W Mielke Jr |
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Institution: | 1. Universidad Nacional Autónoma de México , Mexico, D.F., 20-726;2. Colorado State University , Fort Collins, 80523, Colorado |
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Abstract: | Multi-response permutation procedures (MRPP) were recently introduced to test differences between a priori classified groups of objects ( Mielke, Berry Johnson, 1976; Mielke, 1979 ). The null distributions of the MRPP statistics were initially conjectured to be asymptotically normal for some specified conditions within the setting of a sequence of finite populations due to Madow ( 1948 ). Asymptotic normality of a class of MRPP statistics (under the null hypothesis) is shown in two cases: (i) the setting which considers the populations to be the samples resulting from sequential independent identically distributed (i.i.d.) sampling (sampling from infinite populations) and (ii) the setting of a sequence of increasingly large finite populations (sampling from finite populations). The results are direct applications of the weak convergence of a U-statistic process in the i.i.d. case to a Brownian motion (Bhattacharyya and Sen, 1977) and of the weak convergence of a U-statistic process in the finite populations case to a Brownian bridge (Sen, 1972). The conditions are milder for the i.i.d. case than for the finite populations case. However, neither case provides a restriction of a practical consequence in applications of MRPP. In either case, convergence is shown to depend on the asymptotic ratios of the group sizes to the population size. |
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Keywords: | asymptotic normality U-statistics multi-response data weak convergence Brownian motion Brownian bridge sequence of finite populations |
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