Download or read book Confidence Intervals for Predicting Lumber Strength Properties Based on Ratios of Percentiles from Two Weibull Populations written by Richard Arnold Johnson and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ratios of strength properties of lumber are commonly used to calculate property values for standards. Although originally proposed in terms of means, ratios are being applied without regard to position in the distribution. It is now known that lumber strength properties are generally not normally distributed. Therefore, nonparametric methods are often used to derive property values. In some situations, estimating properties based on a parametric estimate is required. For these situations, the three-parameter Weibull distribution looks promising. To use this approach, procedures for estimating confidence intervals for ratios of percentiles from two Weibull populations are needed. In this study, we employed the large sample properties of maximum likelihood estimators to obtain a confidence interval for the ratio of 100Sa-th percentiles from two different three-parameter Weibull distributions. The coverage probabilities were investigated by a computer simulation study. We concluded that the procedure has considerable promise, but many questions remain to be answered.
Download or read book Confidence Intervals for Predicting Lumber Strength Properties Based on Ratios of Percentiles from Two Weibull Populations written by Richard Arnold Johnson and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research Paper FPL RP written by and published by . This book was released on 1986 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Some Bivariate Distributions for Modeling the Strength Properties of Lumber written by Richard Arnold Johnson and published by . This book was released on 1999 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate modeling of the joint stochastic nature of the strength properties of dimension lumber is essential to the determination of reliability-based design safety factors. This report reviews the major techniques for obtaining bivariate distributions and then discusses bivariate distributions whose marginal distributions suggest they might be useful for modeling the joint distribution of two strength properties. Finally, we pick a bivariate Weibull distribution and show that we can write its likelihood function under a proof loading scheme, offering the possibility that it can be used to model the joint distribution of two properties that must each be measured using a destructive test.
Download or read book Moisture Content and Tensile Strength of Douglas Fir Dimension Lumber written by David William Green and published by . This book was released on 1990 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Small sample Solution to the Two sample Problem for Quantiles Using Melded Random Confidence Intervals written by Matthew A. Arvanitis and published by . This book was released on 2022 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new nonparametric solution to the two-sample problem for quantiles is proposed. This solution is applicable to small samples and/or extreme quantiles, and it prioritizes limiting Type I error to the indicated level of significance over optimizing power or confidence interval width. Aside from continuity, no assumptions about the distributions are made. In this approach, nonparametric random confidence intervals obtained from the samples are “melded,” resulting in a nonparametric confidence interval for the difference between the two population quantiles with a specified confidence level. Simulations and an application to lumber strength characteristics are exhibited.
Download or read book A Fit of a Mixture of Bivariate Normals to Lumber Stiffness written by S. P. Verrill and published by . This book was released on 2018 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: It has been common practice to assume that a two-parameter Weibull probability distribution is suitable for modeling lumber strength properties. In a series of papers published from 2012 to 2018, Verrill et al. demonstrated theoretically and empirically that the modulus of rupture (MOR) distribution of a visual grade of lumber or of lumber that has been “binned” by modulus of elasticity (MOE) is not a two parameter Weibull. Instead, the tails of the MOR distribution are thinned via “pseudo-truncation.” The theoretical portion of Verrill et al.’s argument was based on the assumption of a bivariate normal–Weibull MOE–MOR distribution for the full (“mill run”) population of lumber. Verrill et al. felt that it was important to investigate this assumption. In a recent pair of papers, they reported results obtained from a sample of size 200 drawn from a mill run population. They found that normal, lognormal, three-parameter beta, and Weibull distributions did not fit the sample MOR distribution of these data. Instead, it appeared that the MOR data might be fit by a skew normal distribution or a mixture of two univariate normals. In this paper, we investigate whether the joint MOE–MOR data from Verrill et al.’s recent mill run study can be well modeled as a mixture of two bivariate normals.
Download or read book The Strength Properties of Timber written by Princes Risborough Laboratory and published by . This book was released on 1974 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Fit of a Mixture of Bivariate Normals to Lumber Stiffness written by S. P. Verrill and published by . This book was released on 2018 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Improved Confidence Intervals for the Ratio of the Variances and Standard Deviations from Two Normal Populations written by and published by . This book was released on 1978 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shortest confidence intervals for the ration of two variances of normal populations are found as superior alternatives to the widely used equal tail confidence intervals. Extensive tables of high precision are presented which enable the user to easily construct shortest confidence intervals for the ratio of two variances, the ratio of two standard deviations and the shortest unbiased confidence interval for the ratio of two variances. Characteristics and improved performance of the alternative confidence intervals are discussed in detail and illustrated graphically, with an emphasis on the optimal distribution of complementary tail area between the upper and lower tails. (Author).
Download or read book Improved Confidence Intervals for the Ratio of the Variances and Standard Deviations from Two Normal Populations written by Jeffrey Warren Clouse and published by . This book was released on 1978 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shortest confidence intervals for the ration of two variances of normal populations are found as superior alternatives to the widely used equal tail confidence intervals. Extensive tables of high precision are presented which enable the user to easily construct shortest confidence intervals for the ratio of two variances, the ratio of two standard deviations and the shortest unbiased confidence interval for the ratio of two variances. Characteristics and improved performance of the alternative confidence intervals are discussed in detail and illustrated graphically, with an emphasis on the optimal distribution of complementary tail area between the upper and lower tails. (Author).
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2002 with total page 632 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Statistical Methods in Water Resources written by D.R. Helsel and published by Elsevier. This book was released on 1993-03-03 with total page 539 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data on water quality and other environmental issues are being collected at an ever-increasing rate. In the past, however, the techniques used by scientists to interpret this data have not progressed as quickly. This is a book of modern statistical methods for analysis of practical problems in water quality and water resources. The last fifteen years have seen major advances in the fields of exploratory data analysis (EDA) and robust statistical methods. The 'real-life' characteristics of environmental data tend to drive analysis towards the use of these methods. These advances are presented in a practical and relevant format. Alternate methods are compared, highlighting the strengths and weaknesses of each as applied to environmental data. Techniques for trend analysis and dealing with water below the detection limit are topics covered, which are of great interest to consultants in water-quality and hydrology, scientists in state, provincial and federal water resources, and geological survey agencies. The practising water resources scientist will find the worked examples using actual field data from case studies of environmental problems, of real value. Exercises at the end of each chapter enable the mechanics of the methodological process to be fully understood, with data sets included on diskette for easy use. The result is a book that is both up-to-date and immediately relevant to ongoing work in the environmental and water sciences.
Download or read book Probability and Statistics for Engineering and the Sciences Enhanced Webassign Access written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Probability Based Load Criterion for American National Standard A58 written by Bruce R. Ellingwood and published by . This book was released on 1980 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Probability and Statistics Using R written by G. Jay Kerns and published by Lulu.com. This book was released on 2010-01-10 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a textbook for an undergraduate course in probability and statistics. The approximate prerequisites are two or three semesters of calculus and some linear algebra. Students attending the class include mathematics, engineering, and computer science majors.
Download or read book EnvStats written by Steven P. Millard and published by Springer Science & Business Media. This book was released on 2013-10-16 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes EnvStats, a new comprehensive R package for environmental statistics and the successor to the S-PLUS module EnvironmentalStats for S-PLUS (first released in 1997). EnvStats and R provide an open-source set of powerful functions for performing graphical and statistical analyses of environmental data, bringing major environmental statistical methods found in the literature and regulatory guidance documents into one statistical package, along with an extensive hypertext help system that explains what these methods do, how to use these methods, and where to find them in the environmental statistics literature. EnvStats also includes numerous built-in data sets from regulatory guidance documents and the environmental statistics literature. This book shows how to use EnvStats and R to easily: * graphically display environmental data * plot probability distributions * estimate distribution parameters and construct confidence intervals on the original scale for commonly used distributions such as the lognormal and gamma, as well as do this nonparametrically * estimate and construct confidence intervals for distribution percentiles or do this nonparametrically (e.g., to compare to an environmental protection standard) * perform and plot the results of goodness-of-fit tests * compute optimal Box-Cox data transformations * compute prediction limits and simultaneous prediction limits (e.g., to assess compliance at multiple sites for multiple constituents) * perform nonparametric estimation and test for seasonal trend (even in the presence of correlated observations) * perform power and sample size computations and create companion plots for sampling designs based on confidence intervals, hypothesis tests, prediction intervals, and tolerance intervals * deal with non-detect (censored) data * perform Monte Carlo simulation and probabilistic risk assessment * reproduce specific examples in EPA guidance documents EnvStats combined with other R packages (e.g., for spatial analysis) provides the environmental scientist, statistician, researcher, and technician with tools to “get the job done!”
