Showing 1 - 10 of 46
This study considers the theoretical bootstrap “coupling” techniques for nonparametric robust smoothers and quantile … regression, and we verify the bootstrap improvement. To handle the curse of dimensionality, a variant of “coupling” bootstrap … bootstrap method can be used in many situations such as constructing confidence intervals and bands. We demonstrate the …
Persistent link: https://www.econbiz.de/10011189579
We consider testing for discontinuities in a trend function when the residual process exhibits long memory. Using a wavelet decomposition of the estimated trend function into a low-resolution and a high-resolution component, a test statistic is proposed based on blockwise resampling of estimated...
Persistent link: https://www.econbiz.de/10010572292
model estimator. We propose two types of estimators using kernel-based and subsampling methods, and establish their …
Persistent link: https://www.econbiz.de/10010594229
Differential entropy and log determinant of the covariance matrix of a multivariate Gaussian distribution have many applications in coding, communications, signal processing and statistical inference. In this paper we consider in the high-dimensional setting optimal estimation of the...
Persistent link: https://www.econbiz.de/10011263462
It turns out that there exist general covariance matrices associated not only to a random vector itself but also to its general moments. In this paper we introduce and characterize general covariance matrices of a random vector that are associated to some important general moments, which are...
Persistent link: https://www.econbiz.de/10011189578
This paper deals with the problem of estimating the normal covariance matrix relative to the Stein loss. The main interest concerns a new class of estimators which are invariant under a commutator subgroup of lower triangular matrices. The minimaxity of a James–Stein type invariant estimator...
Persistent link: https://www.econbiz.de/10010737755
This paper discusses the problem of testing for high-dimensional covariance matrices. Tests for an identity matrix and for the equality of two covariance matrices are considered when the data dimension and the sample size are both large. Most importantly, the dimension can be much larger than...
Persistent link: https://www.econbiz.de/10010776643
Let X1,…,Xn1+1∼iidNp(μ1,Σ1) and Y1,…,Yn2+1∼iidNp(μ2,Σ2) be two independent random samples, where pn2. In this article, we propose a new test for the proportionality of two large p×p covariance matrices Σ1 and Σ2. By applying modern random matrix theory, we establish the asymptotic...
Persistent link: https://www.econbiz.de/10011041913
Cai et al. (2010) [4] have studied the minimax optimal estimation of a collection of large bandable covariance matrices whose off-diagonal entries decay to zero at a polynomial rate. They have shown that the minimax optimal procedures are fundamentally different under Frobenius and spectral...
Persistent link: https://www.econbiz.de/10011041948
The covariance matrix is embedded in several statistics (such as the trace and general variance) of multivariate statistical analysis. We investigate the trace of the covariance matrix in the context of a two-step monotone incomplete sample drawn from Np+q(μ,Σ), a multivariate normal...
Persistent link: https://www.econbiz.de/10011041982