Analysing multiple observations per subject

2020 ◽  
pp. 439-464
Author(s):  
Janet L. Peacock ◽  
Philip J. Peacock
Keyword(s):  
Statistical Analysis ◽  
Multiple Observations ◽  
Statistical Issues ◽  
Data Point ◽  
Over Time

This chapter describes the statistical issues involved in analysing studies with more than one data point or observation per subject, such as when a series of measurements are made on each individual over time or when a group of subjects are analysed together, forming a cluster. For each of these situations, the statistical analysis needs to take account of the design of the study, and for most situations there are several possible approaches which may be used. The most common approaches are described in terms of when the methods are appropriate, how they work, and how the results are interpreted.

Analysing multiple observations per subject

2010 ◽  
pp. 377-392
Author(s):  
Janet L. Peacock ◽  
Philip J. Peacock
Keyword(s):  
Statistical Analysis ◽  
Longitudinal Data ◽  
Area Under The Curve ◽  
Multiple Observations ◽  
Units Of Analysis ◽  
Key Points ◽  
Serial Data ◽  
Statistical Issues ◽  
Summary Measures ◽  
Over Time

Serial (longitudinal) data 378 Summarizing serial data 380 Calculating area under the curve 382 Other summary measures for serial data 383 Summary measures approach: key points 384 Other approaches to serial data 386 Cluster samples: units of analysis 388 Cluster samples: analysis 390 In this chapter we describe the statistical issues involved in analysing studies with more than one data point or observation per subject, such as when a series of measurements are made on each individual over time or when a group of subjects are analysed together, forming a cluster. For each of these situations, the statistical analysis needs to take account of the design of the study, and for most situations there are several possible approaches which may be used. We describe the most common approaches in terms of when the methods are appropriate, how they work, and how the results are interpreted....

Plasma profiles of IL-6 and TNF with fever-inducing doses of lipopolysaccharide in dogs

1990 ◽  
Vol 259 (1) ◽  
pp. R126-R132 ◽  
Author(s):  
D. R. LeMay ◽  
L. G. LeMay ◽  
M. J. Kluger ◽  
L. G. D'Alecy
Keyword(s):  
Statistical Analysis ◽  
Tumor Necrosis Factor ◽  
Interleukin 6 ◽  
Tumor Necrosis ◽  
Threshold Region ◽  
Plasma Cytokine ◽  
Changes Over Time ◽  
Dose Dependent ◽  
Necrosis Factor ◽  
Over Time

This study was designed to test the tumor necrosis factor (TNF) WEHI 164 clone 13 bioassay and the interleukin 6 (IL-6) B9 bioassay for sensitivity to endogenously produced dog TNF and IL-6 and then to use these assays to examine the associations between these cytokines and lipopolysaccharide (LPS)-induced fever. When dogs were injected with LPS (40, 10, 1, 0.1, and 0.01 microgram/kg), the resulting fever was dose dependent. A plot of plasma cytokine changes over time following LPS injections showed that the plasma TNF-like activity appeared to increase in an all-or-none dose response, whereas the increase in plasma IL-6-like activity appeared to be log dose dependent. Plasma TNF-like and IL-6-like activity were then separately plotted against temperature change (fever). Statistical analysis supported the interpretation that both TNF-like and IL-6-like activity were related to LPS-fever in an all-or-none manner, with IL-6 having a threshold region. We conclude that if these cytokines are circulating mediators of fever, they may induce fever in an all-or-none fashion.

scholarly journals Three Evidence Based Methods to Compensate for a Lack of Subject Background when Ordering Chemistry Monographs

2008 ◽  
Vol 3 (3) ◽  
pp. 3
Author(s):  
Robert A. Wright
Keyword(s):  
Statistical Analysis ◽  
Statistical Significance ◽  
Evidence Base ◽  
Circulation Rate ◽  
Evidence Based ◽  
Practical Application ◽  
Present Evidence ◽  
Library System ◽  
Over Time ◽  
Selection Of

Objective – The aim of this article is to present evidence based methods for the selection of chemistry monographs, particularly for librarians lacking a background in chemistry. These methods will be described in detail, their practical application illustrated, and their efficacy tested by analyzing circulation data. Methods – Two hundred and ninety-five chemistry monographs were selected between 2005 and 2007 using rigorously-applied evidence based methods involving the Library's integrated library system (ILS), Google, and SciFinder Scholar. The average circulation rate of this group of monographs was compared to the average circulation rate of 254 chemistry monographs selected between 2002 and 2004 when the methods were not used or were in an incomplete state of development. Results – Circulations/month were on average 9% greater in the cohort of monographs selected with the rigorously-applied evidence based methods. Further statistical analysis, however, finds that this result can not be attributed to the different application of these methods. Conclusion – The methods discussed in this article appear to provide an evidence base for the selection of chemistry monographs, but their application does not change circulation rates in a statistically significant way. Further research is needed to determine if this lack of statistical significance is real or a product of the organic development and application of these methods over time, making definitive comparisons difficult.

scholarly journals La investigación en pensamiento histórico. Un estudio a través de las tesis doctorales de Ciencias Sociales (1995-2020)

Panta Rei ◽  
2020 ◽  
Vol 14 (2) ◽  
pp. 93-147
Author(s):  
Álvaro Chaparro Sainz ◽  
María del Mar Felices de la Fuente ◽  
Laura Triviño Cabrera
Keyword(s):  
Statistical Analysis ◽  
Methodological Approach ◽  
Historical Thinking ◽  
Systematic Search ◽  
Search Process ◽  
Analysis Program ◽  
Research Gaps ◽  
Doctoral Thesis ◽  
Statistical Analysis Program ◽  
Over Time

Este artículo analiza la evolución de la investigación sobre pensamiento histórico a partir de las tesis doctorales nacionales e internacionales de los últimos veinticinco años. Para ello, se ha seguido un proceso sistemático de búsqueda en las principales bases de datos a nivel mundial, que ha reportado un total de 163 tesis doctorales. Estos trabajos se han analizado desde un enfoque metodológico cuantitativo descriptivo, con el programa de análisis estadístico SPSS y la herramienta Voyant Tools. Los resultados nos ofrecen información acerca del número de investigaciones realizadas, su evolución en el tiempo, los países, idiomas y universidades de mayor producción, y las principales temáticas trabajadas. Concluimos que, pese al aumento de las tesis doctorales sobre pensamiento histórico en los últimos años, continúan existiendo vacíos en la investigación apenas abordados. In this article the evolution of research on Historical Thinking is analyzed based on national and international dissertations defended in the last twenty-five years. For this, we have followed a systematic search process in the main databases worldwide, which has reported a total of 163 dissertations. These works have been analyzed from a descriptive quantitative methodological approach, with the SPSS statistical analysis program and the Voyant Tools tool. The results offer us information about the number of researches carried out, their evolution over time, the countries, languages and universities with the highest production, and the main topics studied. We conclude that, despite the increase in doctoral thesis on Historical Thinking in recent years, there are still research gaps that have hardly been studied.

Evaluation of the land use evolution near solid waste landfills using a new weighted environmental index based on GIS techniques

2021 ◽  
Author(s):  
Javier Rodrigo-Ilarri ◽  
Claudia P. Romero-Hernández ◽  
María-Elena Rodrigo-Clavero
Keyword(s):  
Land Use ◽  
Statistical Analysis ◽  
Land Use Change ◽  
Solid Waste ◽  
Aerial Photographs ◽  
Environmental Index ◽  
Land Occupation ◽  
Gis Techniques ◽  
Anthropogenic Intervention ◽  
Over Time

<p>Land use in the nearby of a Municipal Solid Waste (MSW) landfill can be strongly affected by the waste management tasks (transport, landfilling and closure). Effects extend from the phases prior to the construction of the landfill until years after the completion of the landfilling process in areas located beyond the perimeter of the plot occupied by the landfill. In this work a new methodology for the analysis of land use change over time is presented. The methodology is based on the use of a new environmental index named WEI (Weighted Environmental Index). WEI is based on the use of GIS techniques accounting for different information sources (digital cartography, aerial photographs and satellite images). WEI assigns environmental values to land use based on the degree of anthropogenic intervention and its occupation surface. A georeferenced multitemporal statistical analysis is performed considering the values of WEI previously assigned to every land use. The methodology has been applied to analyze the land use change near the main MSW landfills of Valencia Region (Spain) where landfilling is currently the only waste disposal technique available. Data have been obtained from the Spanish Land Occupation Information System (SIOSE) public database and integrate GIS information about land use/land cover on an extensive, high-detailed scale. Results demonstrate the application of the WEI to real case studies and the importance of integrating statistical analysis of WEI evolution over time to arrive at a better understanding of the socio-economic and environmental processes that induce land-use change.</p>

Representation in the One-Party South

2018 ◽  
pp. 142-171
Author(s):  
Devin Caughey
Keyword(s):  
Statistical Analysis ◽  
Political System ◽  
Median Voter ◽  
Conventional Wisdom ◽  
Marked Contrast ◽  
Ideological Bias ◽  
Congressional Representation ◽  
Southern Conservatism ◽  
The One ◽  
Over Time

This chapter conducts a systematic statistical analysis of congressional representation in the one-party South. Overall, the evidence presented in the previous chapters suggests a political system that was responsive not to a narrow elite only, but to a broad swath of the white public. As such, this chapter examines the responsiveness of Southern members of Congress (MCs) to their white constituents, both cross-sectionally and over time, and compares them to non-Southern MCs. It also shows that Southern MCs responded to the income of the median voter, and examines their ideological bias relative to non-Southern MCs. The chapter then highlights the ways that congressional representation did differ across regions, and discusses how these findings help resolve the “puzzle” of Southern conservatism. In marked contrast to the conventional wisdom, this chapter not only shows that Southern MCs were responsive to their white constituents, but also finds little indication that congressional responsiveness was weaker in the one-party South than in the two-party North, though the mechanisms and character of responsiveness did differ between regions.

Female Authorship in Radiology: Trends in the Past Decade in CARJ

2020 ◽  
pp. 084653712094664
Author(s):  
Nicole Li ◽  
Mostafa Alabousi ◽  
Michael N. Patlas
Keyword(s):  
Logistic Regression ◽  
Statistical Analysis ◽  
P Value ◽  
Inclusion Criteria ◽  
Odds Ratios ◽  
The Past ◽  
Single Author ◽  
Canadian Association ◽  
Female Authorship ◽  
Over Time

Purpose: To identify trends in female authorship in the Canadian Association of Radiologists Journal (CARJ) from 2010 to 2019. Methods: We retrieved papers published in the CARJ over a 10-year period, and retrospectively reviewed 602 articles. All articles except editorials and advertisements were included. We categorized the names of the first and last position authors as female or male and excluded articles that had at least one author of which gender was not known. We compared the trends in the first and last position authors of the articles from 2010 to 2019. For statistical analysis, logistic regression was performed with reported odds ratios (ORs), and a P value of <.05 was defined as statistically significant. Results: Five hundred thirteen articles met inclusion criteria. Among them, 23 articles with a single author were classified as having only a first author. 39.8% (204/513) of first authors were female and 26.9% (132/490) of last authors were female. There has been an overall temporal increase in the odds of both the first and last author being female in CARJ publications (OR: 1.11, P = .034). Similarly, the odds a CARJ publication’s first author being female increased over time (OR: 1.07, P = .033). Female last author did not predict female first author (OR: 1.48, P = .056). There was no association identified between female last author and year of publication (OR: 1.04, P = .225). Conclusion: There has been an overall increase in engagement of female authorship in CARJ.

Study of Carbendazin Residue Accumulation on Greenhouse and Field-Grown Strawberries, after Successive Treatments with Benomyl

1990 ◽  
Vol 73 (4) ◽  
pp. 553-556
Author(s):  
A Mònico-Pifarré ◽  
M Xirau-Vayreda
Keyword(s):  
Statistical Analysis ◽  
Fungal Diseases ◽  
Systemic Fungicide ◽  
Commercial Preparation ◽  
Over Time

Abstract Benomyl, a systemic fungicide used In preharvest treatments to prevent Botrytls and other fungal diseases, metabolizes to carbendazlm (MBC). A study was undertaken to determine if the total residues of MBC of greenhouse and field-grown Douglas strawberries accumulate In fruits after successive fortnightly treatments with a commercial preparation of benomyl. Statistical analysis of the data obtained Indicates that residues of MBC do not accumulate In fruits; on the contrary, they decrease over time.

Lexical expansion in the HAVE and BE perfect in Dutch

Diachronica ◽  
2014 ◽  
Vol 31 (2) ◽  
pp. 159-191 ◽  
Author(s):  
Evie Coussé
Keyword(s):  
Statistical Analysis ◽  
Construction Grammar ◽  
Prototype Theory ◽  
Verb Classes ◽  
Empirical Basis ◽  
Fine Grained ◽  
Legal Texts ◽  
Over Time

This article investigates lexical expansion in the HAVE and BE perfect in Dutch. It is known from previous research that early perfects show more lexical restrictions than their modern counterparts. The aim of this article is to uncover how perfects change their collocational preferences over time. The present study tackles this issue taking a quantitative corpus perspective. The empirical basis for this study is a sample of HAVE and BE perfects taken from a corpus of Dutch legal texts (1250–1800). The sample is analyzed using the method of diachronic distinctive collexeme analysis. The statistical analysis indicates that both perfect constructions show fine-grained shifts in collocational preferences over time. The observed lexical expansion has the following properties: it proceeds (a) gradually, (b) through semantically related verb classes, (c) away from a prototype. These properties are accounted for making use of insights from prototype theory and construction grammar.

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