scholarly journals El método compativo en ecología vegetal

2017 ◽  
pp. 37
Author(s):  
Eduardo Morales
Keyword(s):  
Statistical Analysis ◽  
Statistical Methods ◽  
Phylogenetic Relationships ◽  
Comparative Method ◽  
Comparative Methods ◽  
Statistical Analyses ◽  
Phenotypic Traits ◽  
The Third ◽  
Phylogenetic Inertia ◽  
Ancestral Character Estimation

In this paper a review of the uses of the comparative method in plant eco logy is presented. Particular attention is devoted to statistical methods that analyze variation in continuos phenotypic traits. The comparative method incorporates the phylogenetic relationships of the species in recognition that species usually do not provide independent points in statistical analysis because they share characteristics through descent from common ancestors. This review is divided in three sections. In the first one, the different statistical analysis that comprises the comparative method are presented, particular attention is devoted to: i] Evolutionary correlations, ii] phylogenetic inertia, and iii] ancestral character estimation. The second section presents the different papers that had applied these different methodologies, in both, origin al or reanalyzed data. Finally, in the third section the use of comparative methods to study adaptation and the debate between the use of phylogenetically based statistical methods and conventional statistical analyses are discussed.

scholarly journals Analisis Rasio Keuangan Untuk Menilai Kinerja Keuangan Pada Perusahaan Multifinance Yang Terdaftar Di Bursa Efek Indonesia Periode Tahun 2015-2019

2021 ◽  
Vol 12 (2) ◽  
pp. 189-204
Author(s):  
Turmono ◽  
Mawarto
Keyword(s):  
Financial Performance ◽  
Activity Ratio ◽  
Stock Exchange ◽  
Comparative Method ◽  
Comparative Methods ◽  
Performance Ratio ◽  
The Third ◽  
Solvency Ratio

The objective of this research is to know the best financial performance and the financial performance ratio of multifinance companies listed at Indonesian Stock Exchange reviewed from the analysis of liquidity ratio, solvency ratio, activity ratio and profitability ratio. The method applied is descriptive and comparative methods. The result based on comparative method the ratio in 5 years calculated by the liquidity ratio of the company having the best CR is CFIN because it has the highest ratio of 230.15% and the best CSR is WOMF by 13.44%. The best solvency ratio is CFIN with the lowest DAR and DER ratio is 55.9% and 126.93%. Activity ratio result indicates the best RTO value is WOMF because it has the highest ratio by 0.37 times and the best TATO is ADMF with highest ratio of 0.32 times. The best profitability ratio is achieved by ADMF because it has the highest ROA and ROE ratios of 4.62% and 23.21%. Of total score in 2015-2019 periods, the first rank is occupied by ADMF with score 64, CFIN in the second one with score 84 and WOMF in the third with score 92. 

The Statistics of Causal Inference: A View from Political Methodology

2015 ◽  
Vol 23 (3) ◽  
pp. 313-335 ◽  
Author(s):  
Luke Keele
Keyword(s):  
Statistical Analysis ◽  
Causal Inference ◽  
Statistical Methods ◽  
Statistical Analyses ◽  
Causal Effects ◽  
Causal Relationships ◽  
Causal Interpretation ◽  
Political Methodology ◽  
Statistical Estimates ◽  
Wide Range

Many areas of political science focus on causal questions. Evidence from statistical analyses is often used to make the case for causal relationships. While statistical analyses can help establish causal relationships, it can also provide strong evidence of causality where none exists. In this essay, I provide an overview of the statistics of causal inference. Instead of focusing on specific statistical methods, such as matching, I focus more on the assumptions needed to give statistical estimates a causal interpretation. Such assumptions are often referred to as identification assumptions, and these assumptions are critical to any statistical analysis about causal effects. I outline a wide range of identification assumptions and highlight the design-based approach to causal inference. I conclude with an overview of statistical methods that are frequently used for causal inference.

scholarly journals Evidence of unexplained discrepancies between planned and conducted statistical analyses: a review of randomized trials

2020 ◽  
Author(s):  
Suzie Cro ◽  
Gordon Forbes ◽  
Nicholas A Johnson ◽  
Brennan C Kahan
Keyword(s):  
Statistical Analysis ◽  
Missing Data ◽  
Statistical Methods ◽  
Randomized Trials ◽  
Statistical Analysis Plan ◽  
Trial Data ◽  
Statistical Analyses ◽  
Analysis Approach ◽  
Randomised Trials ◽  
Analysis Model

AbstractBackgroundChoosing or altering the planned statistical analysis approach after examination of trial data (often referred to as ‘p-hacking’) can bias results of randomized trials. However, the extent of this issue in practice is currently unclear. We conducted a review of published randomized trials to evaluate how often a pre-specified analysis approach is publicly available, and how often the planned analysis is changed.MethodsA review of randomised trials published between January and April 2018 in six leading general medical journals. For each trial we established whether a pre-specified analysis approach was publicly available in a protocol or statistical analysis plan, and compared this to the trial publication.ResultsOverall, 89 of 101 eligible trials (88%) had a publicly available pre-specified analysis approach. Only 22/89 trials (25%) had no unexplained discrepancies between the pre-specified and conducted analysis. Fifty-four trials (61%) had one or more unexplained discrepancies, and in 13 trials (15%) it was impossible to ascertain whether any unexplained discrepancies occurred due to incomplete reporting of the statistical methods. Unexplained discrepancies were most common for the analysis model (n=31, 35%) and analysis population (n=28, 31%), followed by the use of covariates (n=23, 26%) and the approach for handling missing data (n=16, 18%). Many protocols or statistical analysis plans were dated after the trial had begun, so earlier discrepancies may have been missed.ConclusionsUnexplained discrepancies in the statistical methods of randomized trials are common. Increased transparency is required for proper evaluation of results.

Relationships between Population Dynamics and Operating Parameters in an Activated Sludge-Plant by Statistical Analysis

1992 ◽  
Vol 25 (4-5) ◽  
pp. 399-400 ◽  
Author(s):  
L. Cingolani ◽  
M. Cossignani ◽  
R. Miliani
Keyword(s):  
Population Dynamics ◽  
Statistical Analysis ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Operating Conditions ◽  
Statistical Analyses ◽  
Operating Parameters ◽  
Aerobic Treatment

Statistical analyses were applied to data from a series of 38 samples collected in an aerobic treatment plant from November 1989 to December 1990. Relationships between microfauna structure and plant operating conditions were found. Amount and quality of microfauna groups and species found in activated sludge proved useful to suggest the possible causes of disfunctions.

scholarly journals Variability of Prognostic Results Based on Biological Parameters in Sickle Cell Disease Cohort Studies in Children: What Should Clinicians Know?

Children ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 143
Author(s):  
Julie Sommet ◽  
Enora Le Roux ◽  
Bérengère Koehl ◽  
Zinedine Haouari ◽  
Damir Mohamed ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Sickle Cell Disease ◽  
Cohort Studies ◽  
Statistical Methods ◽  
Sickle Cell ◽  
Biological Parameters ◽  
Analysis Method ◽  
Cell Disease ◽  
Statistical Analysis Method

Background: Many pediatric studies describe the association between biological parameters (BP) and severity of sickle cell disease (SCD) using different methods to collect or to analyze BP. This article assesses the methods used for collection and subsequent statistical analysis of BP, and how these impact prognostic results in SCD children cohort studies. Methods: Firstly, we identified the collection and statistical methods used in published SCD cohort studies. Secondly, these methods were applied to our cohort of 375 SCD children, to evaluate the association of BP with cerebral vasculopathy (CV). Results: In 16 cohort studies, BP were collected either once or several times during follow-up. The identified methods in the statistical analysis were: (1) one baseline value per patient (2) last known value; (3) mean of all values; (4) modelling of all values in a two-stage approach. Applying these four different statistical methods to our cohort, the results and interpretation of the association between BP and CV were different depending on the method used. Conclusion: The BP prognostic value depends on the chosen statistical analysis method. Appropriate statistical analyses of prognostic factors in cohort studies should be considered and should enable valuable and reproducible conclusions.

scholarly journals Editorial, special issue on “Advances in Robust Statistics”

METRON ◽  
2021 ◽  
Author(s):  
Marco Riani ◽  
Mia Hubert
Keyword(s):  
Statistical Methods ◽  
Robust Statistics ◽  
Statistical Analyses ◽  
Striking Feature ◽  
Special Issue ◽  
Current State ◽  
Editorial Special Issue ◽  
Data Points ◽  
Robust Statistical Methods

AbstractStarting with 2020 volume, the journal Metron has decided to celebrate the centenary since its foundation with three special issues. This volume is dedicated to robust statistics. A striking feature of most applied statistical analyses is the use of methods that are well known to be sensitive to outliers or to other departures from the postulated model. Robust statistical methods provide useful tools for reducing this sensitivity, through the detection of the outliers by first fitting the majority of the data and then by flagging deviant data points. The six papers in this issue cover a wide orientation in all fields of robustness. This editorial first provides some facts about the history and current state of robust statistics and then summarizes the contents of each paper.

Evaluation software for effects produced by MOOC in mediums with different linguistically levels

2018 ◽  
Vol 34 (3) ◽  
pp. 633-645
Author(s):  
Cornel Samoilă ◽  
Doru Ursuţiu ◽  
Vlad Jinga
Keyword(s):  
Statistical Analysis ◽  
Statistical Methods ◽  
Rapid Assessment ◽  
Assessment Method ◽  
Behavioral Changes ◽  
Strong Negation ◽  
Face To Face ◽  
Made In ◽  
The Way

Abstract MOOC appearance has produced, in a first phase, more discussions than contributions. Despite pessimistic opinions or those catastrophic foreseeing the end of the classic education by accepting MOOC, the authors consider that, as it is happening in all situations when a field is reformed, instead of criticism or catastrophic predictions, an assessment should be simply made. MOOC will not be better or worse if it is discussed and dissected but can be tested in action, perfected by results, or abandoned if it has no prospects. Without testing, no decision is valid. A similarity between the MOOC appearance and the appearance of the idea of flying machines heavier than air can be made. In the flight case, the first reaction was a strong negation (including at Academies level) and only performing the first independent flight with an apparatus heavier than air has shifted orientation from denial to contributions. So, practical tests clarified the battle between ideas. The authors of this article encourage the idea of testing–assessment and, therefore, imagined and proposed one software for quickly assess whether MOOC produces changes in knowledge, by simply transferring courses from ‘face-to-face’ environment into the virtual one. Among the methods of statistical analysis for student behavioral changes was chosen the Keppel method. It underpins the assessment method of this work being approached using both the version with one variable and also with three variables. It is intended that this attempts to pave the way for other series of rapid assessment regarding MOOC effects (using other statistical methods). We believe, that this is the only approach that can lead either to improve the system or to renunciation.

Recent and Planned Developments of the Program OxCal

Radiocarbon ◽  
2013 ◽  
Vol 55 (2) ◽  
pp. 720-730 ◽  
Author(s):  
Christopher Bronk Ramsey ◽  
Sharen Lee
Keyword(s):  
Statistical Analysis ◽  
Statistical Methods ◽  
Software Package ◽  
Model Averaging ◽  
Data Sets ◽  
Radiocarbon Dates ◽  
New Approach ◽  
New Models ◽  
Multiphase Models ◽  
Deposition Models

OxCal is a widely used software package for the calibration of radiocarbon dates and the statistical analysis of 14C and other chronological information. The program aims to make statistical methods easily available to researchers and students working in a range of different disciplines. This paper will look at the recent and planned developments of the package. The recent additions to the statistical methods are primarily aimed at providing more robust models, in particular through model averaging for deposition models and through different multiphase models. The paper will look at how these new models have been implemented and explore the implications for researchers who might benefit from their use. In addition, a new approach to the evaluation of marine reservoir offsets will be presented. As the quantity and complexity of chronological data increase, it is also important to have efficient methods for the visualization of such extensive data sets and methods for the presentation of spatial and geographical data embedded within planned future versions of OxCal will also be discussed.

Statistical Analysis of Weather Effects on PM2.5

2012 ◽  
Vol 610-613 ◽  
pp. 1033-1040
Author(s):  
Wei Dai ◽  
Jia Qi Gao ◽  
Bo Wang ◽  
Feng Ouyang
Keyword(s):  
Statistical Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
Statistical Methods ◽  
Predictive Analytics ◽  
Hypothesis Test ◽  
Meteorological Data ◽  
Weather Conditions ◽  
Statistical Distribution ◽  
Weather Effects

Effects of weather conditions including temperature, relative humidity, wind speed, wind and direction on PM2.5 were studied using statistical methods. PM2.5 samples were collected during the summer and the winter in a suburb of Shenzhen. Then, correlations, hypothesis test and statistical distribution of PM2.5 and meteorological data were analyzed with IBM SPSS predictive analytics software. Seasonal and daily variations of PM2.5 have been found and these mainly resulted from the weather effects.

De pensioenbescherming van flexibele werknemers in België

2006 ◽  
Vol 22 (2) ◽  
Author(s):  
Annelies Debels ◽  
Hans Peeters ◽  
Gert Verschraegen ◽  
Jos Berghman
Keyword(s):  
Statistical Analysis ◽  
Old Age ◽  
Pension System ◽  
Panel Study ◽  
Research Strategy ◽  
The Third ◽  
Temporal Flexibility ◽  
Part Time ◽  
Coordinated Regulation ◽  
Pension Benefits

Old age protection of flexible workers in Belgium Old age protection of flexible workers in Belgium This article investigates to what extent the Belgian pension system is adapted to the proliferation of a-typical forms of employment. Are there any differences between the old age protection of flexible and non-flexible workers? What are the effects of flexible employment on participation in the three pension pillars and on the level of pension benefits? To answer these questions, the article pursues a double research strategy: an analysis of Belgian legislation and relevant collective labour agreements is complemented with a statistical analysis on the Panel Study of Belgian Households (PSBH). The analyses show that part-time employment results in a lower pension, while other forms of temporal flexibility such as temporary leave arrangements and temporary unemployment do not. In the second pillar we find that contractual and transitional flexible workers are discriminated. Finally, the results indicate that flexible workers do not compensate for lower pension protection through increased participation in the third pension pillar. Our findings suggest that a re-assessment of the system of ‘assimilated’ periods is required, as well as the development of a system of coordinated regulation for the three pension pillars.

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