Simulated power of the discrete Cramér-von Mises goodness-of-fit tests

The use of goodness-of-fit test statistics for discrete or categorical data is widespread throughout the research community with the Chi- Square the most popular when a researcher aims to determine if observed categorical data differs from a hypothesized multinomial distribution. Even for ordinal categorical data, the use of empirical distribution function (EDF) test statistics such as the Kolmogorov-Smirnov, the three Cramér-von Mises (A2, W2 and U2 as defined below) and various modifications of these are limited in the literature. Power studies of the EDF type test statistics are even more limited. This paper compares the simulated power of the three Cramér-von Mises test statistics with that of the Chi-Square test statistic for a uniform null hypothesis against a variety of alternative distributions which are summarized in Figure 1. Recommendations are made on which is the most powerful test statistic for the predefined alternative distributions.E

Evaluating the statistical power of goodness-of-fit tests for health and medicine survey data

Goodness-of-fit test statistics are widely used in health and medicine related surveys however little regard is usually given to their statistical power. This paper investigates the simulated power of five categorical goodness-of-fit test statistics used to analyze health and medicine survey data collected on a 5-point Likert scale. The test statistics used in this power study are Pearson’s Chi-Square, the Kolmogorov-Smirnov test statistic for discrete data, the Log-Likelihood Ratio, the Freeman-Tukey and the special case of the Power Divergence statistic defined by Cressie and Read (1984). Recommendations based on these simulations are provided on which of these goodness-of-fit test statistics is the most powerful overall and which is the most powerful for the predefined uniform null against the four general shaped alternative distributions (see Figure 1) investigated in this paper

An investigation of neuronal integrity in severe paediatric traumatic brain injury

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Establishing historical sample data is essential for identification of unaccounted Australian soldiers from WWI, WWII, and the Korean War

Mitochondrial DNA (mtDNA) is used for identification of Australian military personnel whose remains are recovered from historical conflicts. A mtDNA sample database does not exist for Australian soldiers that served in World War I (WWI), World War II (WWII) and the Korean War, meaning it is unknown what common haplotypes may have existed among these soldiers, risking identification errors. Haplotype diversity (position 16,024 to 548) was examined in a sample of 254 unrelated WWII-era European-Australians. Of these, 220 different haplotypes were observed, and it is estimated that between 18% and 29% of Australian soldiers who served in historical conflicts have common haplotypes (95% CI). This research demonstrates that mtDNA control region analysis of historical military remains will provide a lower than expected power of discrimination given the population structure of the time, and enlistment policies targeting Australians of European decent. The point estimates for 52% of the common haplotypes obtained in the historical European-Australian sample were not represented in the confidence intervals for European and Western-European EMPOP data. Creation of targeted sample data reflecting correct ancestry of the WWI and II soldiers and additional mtDNA and Y-STR analysis are essential to avoid misidentification of Australian soldiers from historical conflicts

A comparison of thermoregulatory responses to exercise between mass-matched groups with large differences in body fat

We sought to determine 1) the influence of adiposity on thermoregulatory responses independently of the confounding biophysical factors of body mass and metabolic heat production (H(prod)); and 2) whether differences in adiposity should be accounted for by prescribing an exercise intensity eliciting a fixed H(prod) per kilogram of lean body mass (LBM). Nine low (LO-BF) and nine high (HI-BF) body fat males matched in pairs for total body mass (TBM; LO-BF: 88.7 ± 8.4 kg, HI-BF: 90.1 ± 7.9 kg; P = 0.72), but with distinctly different percentage body fat (%BF; LO-BF: 10.8 ± 3.6%; HI-BF: 32.0 ± 5.6%; P < 0.001), cycled for 60 min at 28.1 ± 0.2°C, 26 ± 8% relative humidity (RH), at a target H(prod) of 1) 550 W (FHP trial) and 2) 7.5 W/kg LBM (LBM trial). Changes in rectal temperature (ΔT(re)) and local sweat rate (LSR) were measured continuously while whole body sweat loss (WBSL) and net heat loss (H(loss)) were estimated over 60 min. In the FHP trial, ΔT(re) (LO-BF: 0.66 ± 0.21°C, HI-BF: 0.87 ± 0.18°C; P = 0.02) was greater in HI-BF, whereas mean LSR (LO-BF 0.52 ± 0.19, HI-BF 0.43 ± 0.15 mg·cm(−2)·min(−1); P = 0.19), WBSL (LO-BF 586 ± 82 ml, HI-BF 559 ± 75 ml; P = 0.47) and H(loss) (LO-BF 1,867 ± 208 kJ, HI-BF 1,826 ± 224 kJ; P = 0.69) were all similar. In the LBM trial, ΔT(re) (LO-BF 0.82 ± 0.18°C, HI-BF 0.54 ± 0.19°C; P < 0.001), mean LSR (LO-BF 0.59 ± 0.20, HI-BF 0.38 ± 0.12 mg·cm(−2)·min(−1); P = 0.04), WBSL (LO-BF 580 ± 106 ml, HI-BF 381 ± 68 ml; P < 0.001), and H(loss) (LO-BF 1,884 ± 277 kJ, HI-BF 1,341 ± 184 kJ; P < 0.001) were all greater at end-exercise in LO-BF. In conclusion, high %BF individuals demonstrate a greater ΔT(re) independently of differences in mass and H(prod), possibly due to a lower mean specific heat capacity or impaired sudomotor control. However, thermoregulatory responses of groups with different adiposity levels should not be compared using a fixed H(prod) in watts per kilogram lean body mass

Pedigree derived mutation rate across the entire mitochondrial genome of the Norfolk Island population

Estimates of mutation rates for various regions of the human mitochondrial genome (mtGenome) vary widely, depending on whether they are inferred using a phylogenetic approach or obtained directly from pedigrees. Traditionally, only the control region, or small portions of the coding region have been targeted for analysis due to the cost and effort required to produce whole mtGenome Sanger profiles. Here, we report one of the first pedigree derived mutation rates for the entire human mtGenome. The entire mtGenome from 225 individuals originating from Norfolk Island was analysed to estimate the pedigree derived mutation rate and compared against published mutation rates. These individuals were from 45 maternal lineages spanning 345 generational events. Mutation rates for various portions of the mtGenome were calculated. Nine mutations (including two transitions and seven cases of heteroplasmy) were observed, resulting in a rate of 0.058 mutations/site/million years (95% CI 0.031–0.108). These mutation rates are approximately 16 times higher than estimates derived from phylogenetic analysis with heteroplasmy detected in 13 samples (n = 225, 5.8% individuals). Providing one of the first pedigree derived estimates for the entire mtGenome, this study provides a better understanding of human mtGenome evolution and has relevance to many research fields, including medicine, anthropology and forensics.</p