We introduce an analytical model, the Wald analytical long-distance dispersal (WALD) model, for estimating dispersal kernels of wind-dispersed seeds and their escape probability from the canopy. The model is based on simplifications to well-established three-dimensional Lagrangian stochastic approaches for turbulent scalar transport resulting in a two-parameter Wald (or inverse Gaussian) distri...

Count data often exhibit overdispersion and/or require an adjustment for zero outcomes with respect to a Poisson model. Zero-modified Poisson (ZMP) and zeromodified generalized Poisson (ZMGP) regression models are useful classes of models for such data. In the literature so far only score tests are used for testing the necessity of this adjustment. For this testing problem we show how poor the ...

This paper extends the distributional theory for the problem of testing for structural change in the linear model when the timing of the change is unknown, and proposes a simple method of obtaining approximate critical values for the mean-Wald test. The results apply for a very wide range of regressor types, including integrated and trending regressors, and regressors that exhibit their own str...

We propose a Wald Sequential Probability Ratio Test for analysis of commonly available predictions associated with spacecraft conjunctions. Such predictions generally consist of a relative state and relative state error covariance at the time of closest approach, under the assumption that prediction errors are Gaussian. We show that under these circumstances, the likelihood ratio of the Wald te...

Objectives: To evaluate whether an antenatal and immediate postpartum Edinburgh Postnatal Depression Scale score are predictive of future postpartum depression and observe the correlation in-between the scores and associated risk factors. Methods: Study Design A survey recruiting 345 women from March 2015 to February 2016 using Edinburgh Postnatal Depression Scale for same group of individuals:...

This paper proposes a simple direct testing procedure to distinguish a linear unit root process from a globally stationary three-regime self-exciting threshold autoregressive process. We derive the asymptotic null distribution of the Wald statistic, and show that it does not depend on unknown fixed threshold values. Monte Carlo evidence clearly indicates that the exponential average of the Wald...

References 1. Salari K, Watkins H, Ashley EA. Personalized medicine: hope or hype?. Eur Heart J 2012;33:1564–1570. 2. Phimister EG, Feero WG, Guttmacher AE. Realizing genomic medicine. N Engl J Med 2012:366:757–759. 3. Wald NJ, Hackshaw AK, Frost CD. When can a risk factor be used as a worthwhile screening test? BMJ 1999;319:1562–1565. 4. Wald NJ, Morris JK, Rish S. The efficacy of combining se...

In this paper we consider the Wald test statistic proposed by Watt (1979) for testing equality between the sets of regression coefficients in two linear regression models when the disturbance variances may possibly be unequal. This test can be also used as a test for a structural break. As shown by Ohtani and Toyoda (1985) and Honda and Ohtani (1986), the test based on the Wald test statistic s...

PHENOTYPE PREDICTION AND FEATURE SELECTION IN GENOME-WIDE ASSOCIATION STUDIES by Andrew Roberts Genome wide association studies (GWAS) search for correlations between single nucleotide polymorphisms (SNPs) in a subject genome and an observed phenotype. GWAS can be used to generate models for predicting phenotype based on genotype, as well as aiding in identification of specific genes affecting ...