Article
Mathematical & Computational Biology
Roland G. G. Gera, Tim Friede
Summary: The increasing interest in subpopulation analysis in personalized medicine and targeted therapies has led to the development of various new trial designs and analysis methods. This paper proposes a trial design applicable to any set of composite populations and considers normally distributed endpoints and random baseline covariates. The study uses p-values calculated on subset levels and the inverse normal combination function to test treatment effects for composite populations, while also accounting for multiple testing using the closed testing procedure. The paper also derives critical boundaries for intersection hypothesis tests and provides simulations demonstrating the absence of practical relevant inflation of the type I error rate. The target power after sample size recalculation is typically met or close to being met.
BIOMETRICAL JOURNAL
(2023)
Article
Computer Science, Interdisciplinary Applications
Lukas Baumann, Maximilian Pilz, Meinhard Kieser
Summary: The sample size of a clinical trial depends not only on error rates and effect sizes, but also on nuisance parameters. When uncertainty is high, an internal pilot study design can be used to achieve target power. The blindrecalc package helps with planning such a trial design.
Article
Mathematical & Computational Biology
Anna Poehlmann, Frank Konietschke
Summary: Sample size calculations for two (independent) samples are well-established in (pre-)clinical research. When planning multiple samples, sample size planning tools based on analysis of variance methods are commonly used. This study employs multiple contrast test procedures for sample size computations in both parametric and nonparametric designs, using Steel-type tests. Extensive simulations were conducted to evaluate the accuracy of the approximate solutions, and the developed procedures were found to be valuable in planning (pre-)clinical trials with multiple samples.
BIOMETRICAL JOURNAL
(2023)
Article
Statistics & Probability
Davy Paindaveine, Josea Rasoafaraniaina, Thomas Verdebout
Summary: This paper investigates preliminary test estimation based on multiple tests, discusses the asymptotic and finite-sample behaviors in k-sample covariance estimation, and demonstrates their practical relevance in a supervised classification framework.
JOURNAL OF THE AMERICAN STATISTICAL ASSOCIATION
(2022)
Article
Economics
Robert Garlick, Joshua Hyman
Summary: In this study, researchers evaluated the performance of different sample selection correction methods using a natural experiment. They found that less restrictive semi-parametric correction methods tend to outperform parametric correction methods, but do not perform better than simple OLS regressions. Models using more covariates with less coarse distributions generally perform better than those using only a few discrete covariates.
JOURNAL OF BUSINESS & ECONOMIC STATISTICS
(2022)
Article
Food Science & Technology
Joseph Kumphanda, Limbikani Matumba, Maurice Monjerezi, Thomas B. Whitaker, Sarah De Saeger, Hussaini Anthony Makun
Summary: This study reports a significant decline in sample and test portion masses used for mycotoxin quantification in maize between 1991 and 2020. The emphasis on standardized sampling plans and laboratory sample size for maize seems to be increasingly overlooked. This oversight may lead to increased uncertainty in estimating the true mycotoxin concentration in grain lots.
Article
Computer Science, Theory & Methods
Teemu Sailynoja, Paul-Christian Buerkner, Aki Vehtari
Summary: The study presents new methods based on the probability integral transformation (PIT) for assessing the goodness of fit between a given sample and a reference distribution. These methods provide simultaneous confidence bands for testing uniformity and multiple sample comparisons. They can also be applied in cases where the reference distribution is represented by a finite sample, which is useful for simulation-based calibration.
STATISTICS AND COMPUTING
(2022)
Article
Mathematical & Computational Biology
Liji Shen, Jin Zhang, Paul DeLucca
Summary: This article discusses the selection of appropriate dose in a multiple-dose clinical trial and addresses the issue of overestimating the true response rate. The Stepwise Overcorrection method is used to control the Type I error in statistical inference, and a maximum-minimum strategy is proposed to ensure the desired statistical power of detecting differences in response rates.
STATISTICS IN BIOPHARMACEUTICAL RESEARCH
(2023)
Article
Ecology
Garrett M. Street, Jonathan R. Potts, Luca Borger, James C. Beasley, Stephen Demarais, John M. Fryxell, Philip D. McLoughlin, Kevin L. Monteith, Christina M. Prokopenko, Miltinho C. Ribeiro, Arthur R. Rodgers, Bronson K. Strickland, Floris M. van Beest, David A. Bernasconi, Larissa T. Beumer, Guha Dharmarajan, Samantha P. Dwinnell, David A. Keiter, Alexine Keuroghlian, Levi J. Newediuk, Julia Emi F. Oshima, Olin Rhodes, Peter E. Schlichting, Niels M. Schmidt, Eric Vander Wal
Summary: Sample size sufficiency is crucial for estimating resource selection functions (RSFs) from GPS-based animal telemetry, with thresholds such as M >= 30 captured animals and maximum relocations per animal N recommended. This study provides a comprehensive solution by deriving mathematical expressions for necessary M and N based on biologically meaningful quantities, showing the decline in required sample sizes with increasing selection strength and landscape complexity. Analytical solutions demonstrate that the most relevant effects on utilization distribution can often be estimated with fewer than M=30 animals, regardless of availability definition, and should be a mandatory component for all future RSF studies.
METHODS IN ECOLOGY AND EVOLUTION
(2021)
Article
Materials Science, Composites
Bo-Wen Guan, Yuan-Yuan Zhang, Yuan-Qing Li, Shao-Yun Fu
Summary: According to literature and standards, the minimum sample size for friction testing of thermoplastics is usually 3-5. However, the applicability of this size for short fiber reinforced polymer composites with inhomogeneous structures is unclear. In this study, 100 friction samples of short carbon fiber reinforced polyetherimide (SCF/PEI) composites are prepared and their friction coefficients are measured. The results show good agreement with several mathematical distributions, and a method for determining the minimum sample size is proposed based on Monte Carlo Simulation.
POLYMER COMPOSITES
(2023)
Article
Mathematical & Computational Biology
Kevin K. Dobbin, Lisa M. McShane
Summary: Treatment selection biomarkers are useful in guiding therapy choice and require evaluation in appropriate studies. This study develops a novel sample size method for estimating the benefit of biomarker-guided therapy relative to standard care. The method combines Monte Carlo and regression, and performs well under different scenarios.
STATISTICS IN MEDICINE
(2022)
Article
Health Care Sciences & Services
Bosheng Li, Liwen Su, Jun Gao, Liyun Jiang, Fangrong Yan
Summary: The article introduces a design aimed at improving the delayed treatment effect in immunotherapy trials and points out the limitations and drawbacks of traditional designs. By applying group sequential design and one-dimensional search algorithm, the efficiency and power of the trial are improved, and a new design that saves sample size is proposed.
STATISTICAL METHODS IN MEDICAL RESEARCH
(2021)
Review
Materials Science, Multidisciplinary
Ping Tao, Wei Zhou, Xinting Miao, Jian Peng, Wenming Liu
Summary: This paper reviews recent progress in the characterization of hydrogen embrittlement achieved via small-sized sample testing methods, including tensile tests, small punch tests, and nanoindentation tests. It discusses the advantages of using small-sized specimens for direct observations of hydrogen influences on mechanical properties and microstructure evolution. It also examines the quantitative analysis of hydrogen embrittlement sensitivity and the interaction between hydrogen and dislocation in metals through small punch tests and nanoindentation tests.
Article
Environmental Sciences
Xiongfeng Du, Songsong Gu, Zheng Zhang, Shuzhen Li, Yuqi Zhou, Zhaojing Zhang, Qi Zhang, Linlin Wang, Zhicheng Ju, Chengliang Yan, Tong Li, Danrui Wang, Xingsheng Yang, Xi Peng, Ye Deng
Summary: Soil bacterial communities in a coastal area follow a distance-decay relationship and the distribution is influenced by body size. This study collected soil samples from two adjacent ecosystems and found that the entire microbial community, as well as individual taxonomic groups, exhibited distance-decay patterns. The turnover rate of microbial communities was higher in nontidal soils and topsoil, with body size influencing the spatial limitation in nontidal topsoil but not in tidal soils.
ENVIRONMENTAL RESEARCH
(2023)
Article
Public, Environmental & Occupational Health
Yongdong Ouyang, Fan Li, John S. Preisser, Monica Taljaard
Summary: There has been a surge of interest in stepped-wedge cluster randomized trials (SW-CRTs) in recent years, leading to the rapid development of methodologies and various power and sample size calculation software. Researchers can benefit from reviewing and understanding the features of existing calculators to choose the most appropriate one for their trials, ultimately improving the accuracy of sample size and power calculations.
INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
(2022)
