Variance estimation from systematic samples in Minnesota timber stands

1983 ◽  
Vol 13 (6) ◽  
pp. 1255-1257 ◽  
Author(s):  
Carol A. Reber ◽  
Alan R. Ek
Keyword(s):  
Variance Estimation ◽  
Basal Area ◽  
Simple Random Sample ◽  
Systematic Sampling ◽  
University Of Minnesota ◽  
Sampling Errors ◽  
Forest Survey ◽  
Lake States ◽  
The Individual ◽  
The University

A 402 permanent-plot inventory of the University of Minnesota Cloquet Forestry Center was used to assess the adequacy of systematic samples for estimating population variance. The inventory plots were arranged in the form of four approximately equal-size systematic samples or clusters. The design was systematic sampling with multiple random starts. Population variances were estimated for number of trees, basal area, and volume per hectare for four different measurements spanning 17 years. Results indicate that the individual random starts and the aggregate of 402 plots treated as a simple random sample provide estimates of variance comparable to those obtained by treating the inventory as a cluster sample design. This report plus reports in the literature suggest that plots in the Lake States that are at least 80 to 362 m apart are likely to provide useful estimates of population variances and sampling errors for common forest-survey variables.

Advancing Wellbeing in People, Organizations, and Communities

2018 ◽  
pp. 67-81
Author(s):  
Mary Jo Kreitzer ◽  
Louise Delagran ◽  
Andrea Uptmor
Keyword(s):  
Evidence Based ◽  
University Of Minnesota ◽  
Core Component ◽  
Santa Monica ◽  
The Individual ◽  
The Uk ◽  
The University ◽  
The Way

Wellbeing goes beyond the management of disease or illness; it is a larger concept that is characterized by a general contentment in life and the way things are. This chapter uses the framework of the University of Minnesota Wellbeing Model to explore the evidence-based factors that influence wellbeing, including health, relationships, security, purpose, environment, and community. Mindfulness, a way of being that provides another core component of wellbeing, is defined and its evidence based discussed. Exemplars of wellbeing at the individual, organizational, and society level are described. Some applications of similar models in towns such as Albert Lea, Minnesota, Austin, Texas, and Santa Monica, California, are discussed, as well as initiatives in Canada and the UK.

scholarly journals Systematic Sampling for Estimating Harvest-Induced Changes of a Forest Stand

2009 ◽  
Vol 9 (1) ◽  
pp. 39-55
Author(s):  
Dennis Peque ◽  
Keyword(s):  
Sample Size ◽  
Standard Error ◽  
Basal Area ◽  
Systematic Sampling ◽  
Relative Standard Error ◽  
Stem Density ◽  
Relative Standard ◽  
The Individual ◽  
Induced Changes ◽  
Forest District

This study was conducted in Compartment 2012a in Bosinghausen Forest District in Germany covering an area of 5 hectared. Twenty two sampling plots were laid out in the field following systematic sampling design. Results showed that all estimates for all variables (e.g. tree heights, DBH, stem density, basal area and volume) under trees that were marked for cutting have higher relative standard error. This was due to higher dispersion of individual estimates in each plot. On the other hand, the simulation study shows that sampling efficiency can be acheived by increasing the sample size. When more samples are included, the relative standard error becomes low. From this study, it can be concluded that the variability of the estimates were affected by sample size and the variability of individual units in the population or the individual esitmates (in this case, estimates in each plot).

A New Emphasis in Strategies for Developing Lignin-Based Plastics

1990 ◽  
Vol 197 ◽  
Author(s):  
Sunil Dutta ◽  
Simo Sarkanen
Keyword(s):  
Noncovalent Interactions ◽  
Chemical Species ◽  
Polymeric Materials ◽  
The United States ◽  
Kraft Lignin ◽  
Size Exclusion ◽  
University Of Minnesota ◽  
The Individual ◽  
The University ◽  
Molecular Components

ABSTRACTLignins, a truly abundant group of biopolymers exhibiting some significant diversity, are usually thought to be constituted by a random proportionate distribution of ten different linkages between p-hydroxphenylpropane units. Over 20 million tons of kraft lignin derivatives are produced annually in the United States by the pulping industry, but 99.9% of these aromatic polymeric materials are consumed as fuel. Such industrial byproducts are generally viewed as being almost hopelessly complicated mixtures of partially degraded and condensed chemical species. However, a very different picture has begun to emerge from a more coherent understanding of the physicochemical behavior exhibited by kraft lignin preparations. Noncovalent interactions between the individual molecular components under a variety of solution conditions orchestrate pronounced associative processes that are characterized by a remarkable degree of specificity. Their consequences may be readily observed both size-exclusion chromatographically and electron microscopically, and are reflected in an anomalous variation of glass transition temperature, Tg, with molecular weight of paucidisperse kraft lignin fractions. How these effects may influence the mechanical properties of lignin-based polymeric materials is presently being scrutinized at the University of Minnesota.

Generalized biomass equations for jack and red pine in the Lake States

1982 ◽  
Vol 12 (4) ◽  
pp. 913-921 ◽  
Author(s):  
David H. Alban ◽  
Paul R. Laidly
Keyword(s):  
Geographical Area ◽  
Basal Area ◽  
Tree Height ◽  
Stem Bark ◽  
Jack Pine ◽  
Red Pine ◽  
Individual Tree ◽  
Stem Wood ◽  
Lake States ◽  
The Individual

The biomass of 76 jack pine (Pinusbanksiana Lamb.) trees (29 stands) and 72 red pine (P. resinosa Ait.) trees (28 stands) from throughout the northern Lake States was determined. All trees were from even-aged, unthinned plantations ranging from 20–61 years old; site indexes represented nearly the complete range for these species. Individual tree component weights (foliage, live branches, dead branches, stem wood, and stem bark) were regressed against dbh and tree height using the nonlinear form Bt = aDbHc. Stand biomass was also estimated with stand basal area and mean height of dominant and codominant trees using the equation form Bs = a + b(B) + c(Hs) or a + b(B)(Hs). The equations were tested in two additional stands of red pine and two of jack pine and by comparison with literature values. Individual tree equations were most accurate for estimating bole components and the total tree and less accurate for foliage and branches. The standard error of the estimate divided by mean weight ranged from 0.06 to 0.17 for bole components, from 0.21 to 0.28 for live crown components, and from 0.43 to 0.49 for dead branches. For all components, jack pine equations were slightly less precise than those for red pine. The individual tree equations appear to be applicable over a wide geographical area and usable for both natural stands and plantations. The equations appear to be valid for the majority of unthinned stands in the age range of 20–50 years. The stand equations, while less precise than individual tree estimates, should give reasonably accurate estimates of stand biomass components in most situations.

Systematic sampling

2019 ◽  
pp. 48-67
Author(s):  
David G. Hankin ◽  
Michael S. Mohr ◽  
Ken B. Newman
Keyword(s):  
Random Sample ◽  
Variance Estimation ◽  
Random Order ◽  
Selection Method ◽  
Unbiased Estimation ◽  
Simple Random Sample ◽  
Systematic Sampling ◽  
Sampling Variance ◽  
Systematic Sample ◽  
Rule Out

In many contexts it is difficult or impossible to select a simple random sample. For example, the number of units in the finite population, N, may not be known in advance, or it may not be feasible to assign labels to all units in the population and to select an SRS from these labels (e.g., crabs within boxes on a fishing vessel). Instead, one may select a random start, r, on the integers 1 through k and then select that unit and every kth unit thereafter for inclusion in the sample. This selection method, called linear systematic sampling, results in an extremely restricted randomization—there are only k possible linear systematic samples—compared to the typically large number [N!/(N-n)!n!] of possible samples of size n that can be selected from N by SRS. If units are in random order, then linear systematic sampling with mean-per-unit estimation will have sampling variance comparable to SRS with mean-per-unit estimation. But if there is a trend of increase or decrease in unit-specific y value with unit label or location, then sampling variance of a mean-per-unit estimator for a linear systematic design may be substantially less than for an SRS design. Circular and fractional interval systematic sampling designs are also presented. The disadvantage of these systematic sampling designs is that the highly restricted randomizations generally rule out unbiased estimation of sampling variance from a single systematic sample. Several approaches for variance estimation are considered.

The Effects of Presentation on Noise and Dental Appliances on Speech

1981 ◽  
Vol 24 (1) ◽  
pp. 151-151
Author(s):  
Lillian Glass ◽  
Sharon R. Garber ◽  
T. Michael Speidel ◽  
Gerald M. Siegel ◽  
Edward Miller
Keyword(s):  
Southern California ◽  
University Of Southern California ◽  
University Of Minnesota ◽  
School Of Medicine ◽  
Southern California School ◽  
School Of Dentistry ◽  
The University

An omission in the Table of Contents, December JSHR, has occurred. Lillian Glass, Ph.D., at the University of Southern California School of Medicine and School of Dentistry, was a co-author of the article "The Effects of Presentation on Noise and Dental Appliances on Speech" along with Sharon R. Garber, T. Michael Speidel, Gerald M. Siegel, and Edward Miller of the University of Minnesota, Minneapolis.

Integrating Legacy Laboratory Information Systems into a Client-Server World: The University of Minnesota Clinical Workstation (CWS) Project

1995 ◽  
Vol 34 (03) ◽  
pp. 289-296 ◽  
Author(s):  
B. H. Sielaff ◽  
D. P. Connelly ◽  
K. E. Willard
Keyword(s):  
Information Systems ◽  
Clinical Decision ◽  
Database Management System ◽  
University Of Minnesota ◽  
Client Server ◽  
Clinical Workstation ◽  
Future Hospital ◽  
The Cost ◽  
The University ◽  
Laboratory Information Systems

Abstract:The development of an innovative clinical decision-support project such as the University of Minnesota’s Clinical Workstation initiative mandates the use of modern client-server network architectures. Preexisting conventional laboratory information systems (LIS) cannot be quickly replaced with client-server equivalents because of the cost and relative unavailability of such systems. Thus, embedding strategies that effectively integrate legacy information systems are needed. Our strategy led to the adoption of a multi-layered connection architecture that provides a data feed from our existing LIS to a new network-based relational database management system. By careful design, we maximize the use of open standards in our layered connection structure to provide data, requisition, or event messaging in several formats. Each layer is optimized to provide needed services to existing hospital clients and is well positioned to support future hospital network clients.

‘A Routh O’ Auld Nick-Nackets’ – the antiquarian collection of John Rae

2015 ◽  
Vol 36-37 (1) ◽  
pp. 163-183
Author(s):  
Paul Taylor
Keyword(s):  
United States ◽  
Nineteenth Century ◽  
Social Context ◽  
Moral Education ◽  
The United States ◽  
Representative Case ◽  
National Museums ◽  
The Individual ◽  
The University

John Rae, a Scottish antiquarian collector and spirit merchant, played a highly prominent role in the local natural history societies and exhibitions of nineteenth-century Aberdeen. While he modestly described his collection of archaeological lithics and other artefacts, principally drawn from Aberdeenshire but including some items from as far afield as the United States, as a mere ‘routh o’ auld nick-nackets' (abundance of old knick-knacks), a contemporary singled it out as ‘the best known in private hands' (Daily Free Press 4/5/91). After Rae's death, Glasgow Museums, National Museums Scotland, the University of Aberdeen Museum and the Pitt Rivers Museum in Oxford, as well as numerous individual private collectors, purchased items from the collection. Making use of historical and archive materials to explore the individual biography of Rae and his collection, this article examines how Rae's collecting and other antiquarian activities represent and mirror wider developments in both the ‘amateur’ antiquarianism carried out by Rae and his fellow collectors for reasons of self-improvement and moral education, and the ‘professional’ antiquarianism of the museums which purchased his artefacts. Considered in its wider nineteenth-century context, this is a representative case study of the early development of archaeology in the wider intellectual, scientific and social context of the era.

Sign in / Sign up

Export Citation Format

Share Document