항목

  • Principal component regression
    PLS) estimator. Similar to PCR, PLS also uses derived covariates of lower dimensions. However unlike PCR, the derived covariates for PLS are obtained based on using both the outcome as well as the covariates. While PCR seeks the high variance directions in the space of the covariates, PLS seeks...
  • Hájek–Le Cam convolution theorem
    ell(\theta) is the score function, and ′ denotes matrix transpose. Theorem . Suppose Tn is a uniformly (locally) regular estimator of the parameter q. Then There exist independent random m-vectors \scriptstyle Z_\theta\,\sim\,\mathcal{N}(0,\,I^{-1}_{q(\theta)}) and Δθ such that where d denotes...
  • Allan variance
    between measurements is denoted with T, which is the sum of observation time τ and dead-time. Fixed τ estimators A first simple estimator would be to directly translate the definition into \sigma_y^2(\tau, M) = \text{AVAR}(\tau, M) = \frac{1}{2(M-1)} \sum_{i=0}^{M-2}(\bar{y}_{i+1}-\bar{y}_i)^2...
  • Average absolute deviation
    robust estimator of dispersion.For the example {2, 2, 3, 4, 14}: 3 is the median, so the absolute deviations from the median are {1, 1, 0, 1, 11} (reordered as {0, 1, 1, 1, 11}) with a median of 1, in this case unaffected by the value of the outlier 14, so the median absolute deviation (also...
  • Weighted arithmetic mean
    our estimator we need to pre-divide by 1 - \left(V_2 / V_1^2\right) , ensuring that the expected value of the estimated variance equals the actual variance of the sampling distribution.The final unbiased estimate of sample variance is: \begin{align} s^2\ &= \frac{\hat \sigma^2_\mathrm{weighted...
  • Epigenetic clock
    age estimator was developed using 8,000 samples from 82 Illumina DNA methylation array datasets, encompassing 51 healthy tissues and cell types. The major innovation of Horvath's epigenetic clock lies in its wide applicability: the same set of 353 CpGs and the same prediction algorithm is used...
  • Optimal design
    unbiased estimator of a predetermined linear combination of model parameters. D-optimality (determinant) A popular criterion is D-optimality, which seeks to minimize |(X'X)−1|, or equivalently maximize the determinant of the information matrix X'X of the design. This criterion results in...
  • Multivariate kernel density estimation
    cross validation and plug-in selectors. The plug-in (PI) estimate of the AMISE is formed by replacing Ψ4 by its estimator \hat{\bold{\Psi}}_4 \operatorname{PI}(\bold{H}) = n^{-1} |\bold{H}|^{-1/2} R(K) + \tfrac{1}{4} m_2(K)^2 (\operatorname{vec}^T \bold{H}) \hat{\bold{\Psi}}_4 (\bold{G...
  • Minimum mean square error
    or cannot be found. Let x be a n \times 1 hidden random vector variable, and let y be a m \times 1 known random vector variable (the measurement or observation), both of them not necessarily of the same dimension. An estimator \hat{x}(y) of x is any function of the measurement y. The estimation...
  • Zero-inflated model
    estimators are given by \hat{\lambda}_{mo} = \frac{s^2+m^2-m}{m}, \hat{\pi}_{mo} = \frac{s^2 - m}{s^2 + m^2 - m}, where m is the sample mean and s^2 is the sample variance.The maximum likelihood estimator can be found by solving the following equation \bar{x}(1- e^{-\hat{\lambda}_{ml}}) = \hat...
  • Effect size 效应值
    unbiased estimator is \hat{\sigma}^2(g^*) = \frac{n_1+n_2}{n_1 n_2} + \frac{(g^*)^2}{2(n_1 + n_2)}. \phi = \sqrt{ \frac{\chi^2}{N}} \phi_c = \sqrt{ \frac{\chi^2}{N(k - 1)}} Phi (φ) Cramér's V (φc) Commonly used measures of association for the chi-squared test are the Phi coefficient and...
  • Simultaneous equations model
    end{bmatrix} Several estimators belong to this class: κ=0: OLS κ=1: 2SLS. Note indeed that in this case, I-\kappa M = I-M= P the usual projection matrix of the 2SLS κ=λ: LIML κ=λ - α (n-K): estimator. Here K represents the number of instruments, n the sample size, and α a positive...
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