scholarly journals Consequences and Recurrence of Dangerous Occurrences in Air Transport in 1919-2018

2021 ◽  
Vol 7 (3) ◽  
pp. 42-55
Author(s):  
Jarosław KOZUBA ◽  
Stanisław Sirko ◽  
Jan Pila
Keyword(s):  
Computer Programs ◽  
Air Transport ◽  
Measurement Scale ◽  
Technological Advancement ◽  
Statistical Research ◽  
Time Intervals ◽  
Significance Level ◽  
Research Results ◽  
Statistical Hypotheses ◽  
Research Questions

The paper presents statistical research results regarding the occurrence of which dangerous aviation events in 1919-2018. The source of the information about the events was the AviationSafetyNetwork website. With the use of Excel 2016 and Statistica v. 12 computer programs, five-time intervals were identified in which hazardous aviation incidents took place.Characterizing the distribution of these events in all periods, due to the technological advancement and capabilities of airplanes, the distribution of dangerous events in the last three periods was compared. The following tests were used to verify the statistical hypotheses: , Shapiro-Wilk, Brown-Forsythe, Kruskal-Wallis. When choosing the appropriate test, the following factors were taken into account: the type of measurement scale, the dependence/independence of samples, and their number. The standard significance level was assumed to be α = 0.05. The consequences and repeatability of aviation events in the identified time intervals were analyzed. The research questions that were posed were the following: in which seasons of the year, months, days of the month, and days of the week did the most dangerous events deaths occur? How often did dangerous events take place? Was the distribution of events similar in the identified periods? The results of the conducted research allowed to identify five periods in which hazardous events took place and demonstrate that in particular periods the distribution of hazardous air events in subsequent seasons, months, and days of the week was not the same.

scholarly journals Color stability of ceramic brackets immersed in potentially staining solutions

2015 ◽  
Vol 20 (4) ◽  
pp. 32-38 ◽  
Author(s):  
Bruna Coser Guignone ◽  
Ludimila Karsbergen Silva ◽  
Rodrigo Villamarim Soares ◽  
Emilio Akaki ◽  
Marcelo Coelho Goiato ◽  
...  
Keyword(s):  
Profile Analysis ◽  
Artificial Saliva ◽  
Rocky Mountain ◽  
Color Stability ◽  
Bonferroni Correction ◽  
Time Intervals ◽  
Significance Level ◽  
Paired Samples ◽  
Immersion Period ◽  
Ceramic Brackets

OBJECTIVE: To assess the color stability of five types of ceramic brackets after immersion in potentially staining solutions.METHODS: Ninety brackets were divided into 5 groups (n = 18) according to brackets commercial brands and the solutions in which they were immersed (coffee, red wine, coke and artificial saliva). The brackets assessed were Transcend (3M/Unitek, Monrovia, CA, USA), Radiance (American Orthodontics, Sheboygan, WI, USA), Mystique (GAC International Inc., Bohemia, NY, USA) and Luxi II (Rocky Mountain Orthodontics, Denver, CO, USA). Chromatic changes were analyzed with the aid of a reflectance spectrophotometer and by visual inspection at five specific time intervals. Assessment periods were as received from the manufacturer (T0), 24 hours (T1), 72 hours (T2), as well as 7 days (T3) and 14 days (T4) of immersion in the aforementioned solutions. Results were submitted to statistical analysis with ANOVA and Bonferroni correction, as well as to a multivariate profile analysis for independent and paired samples with significance level set at 5%.RESULTS: The duration of the immersion period influenced color alteration of all tested brackets, even though these changes could not always be visually observed. Different behaviors were observed for each immersion solution; however, brackets immersed in one solution progressed similarly despite minor variations.CONCLUSIONS: Staining became more intense over time and all brackets underwent color alterations when immersed in the aforementioned solutions.

scholarly journals DISPARITIES IN THE PERCEPTION OF BUSINESS RISKS IN CONNECTION WITH THE ACHIEVED EDUCATION OF THE OWNER/MANAGER AND DOING BUSINESS

2021 ◽  
Vol 9 (1) ◽  
pp. 25-40
Author(s):  
Ján Dvorský ◽  
Jaroslav Belás, Jr. ◽  
Gentjan Çera ◽  
Svitlana Bilan
Keyword(s):  
Employee Turnover ◽  
Chi Square ◽  
Legal Risk ◽  
Research Results ◽  
Doing Business ◽  
Risk Sources ◽  
Statistical Hypotheses ◽  
Chi Square Test ◽  
The Relationship ◽  
Visegrád Countries

The article aims to identify disparities in the perception of business risks connected with the achieved education of the owner/manager and doing business in the SME segment. The study's empirical part was realised on 1585 fulfil questionnaires of SMEs in the Visegrad countries (V4). The Chi-square test and Z-test verified the formulated statistical hypotheses. The research results brought a common and different perception of business risks between the examined groups of entrepreneurs. The results showed that the relationship between education and the entrepreneur's business area is not a statistically significant factor in the perception of market, financial and legal risk sources. On the contrary, disparities are significant in the perception of selected sources of management, strategic and personnel risk, between groups of entrepreneurs regarding the relationship between education and the business of the entrepreneur. Entrepreneurs whose education is related to the area of business perceive the sources of personnel risk (employee turnover and the effort of employees to increase their performance) more positively than entrepreneurs whose education is not related to business.

scholarly journals The influence of environment forming factors on the productivity of winter wheat

2021 ◽  
Vol 207 (04) ◽  
pp. 9-16
Author(s):  
Valeriy Burluckiy ◽  
Polina Semeshkina ◽  
Vladimir Mazurov
Keyword(s):  
Winter Wheat ◽  
Statistical Processing ◽  
Mineral Fertilizers ◽  
First Year ◽  
Wheat Grain ◽  
Significance Level ◽  
Research Results ◽  
Yield And Quality ◽  
Close Relationship

Abstract. The goal is to study the influence of the predecessor and fertilizers on the yield and quality of winter wheat grain. Methods. The studies were carried out in a long-term stationary field experiment on a gray forest medium loamy soil. Field experience, observations, accounting and generalization of research results were carried out in accordance with the methodological recommendations of B.A. Dospekhov. Statistical processing of the research results was performed using Microsoft Excel 2007 with a 95 % significance level of the results. Results. As a result of the studies, it was noted that the studied predecessors had an insignificant effect on the development of winter wheat plants in the initial phases of growth. The density of winter wheat plants during the germination period varied within the range of 314–323 psc/m2 without the use of fertilizers and 317–328 psc/m2 against the background of their application. Further growth and development of plants took place in close relationship with the studied factors. At the end of the growing season, the number of productive stems was higher on the plots, where the clover of the first year of use was used as a predecessor, both in the control (without fertilizers) and when applying mineral fertilizers. Accordingly, the yield of winter wheat grain was higher for this predecessor, averaging 35.7 c/ha for 2014–2019. Without fertilization, depending on the predecessor, 25.2–32.8 c/ha were obtained, against the background of fertilization – 34.2–39.6 c/ha of winter wheat grain. On average, over the years of research, winter wheat grain contained 10.7–14.0 % protein. Depending on the year, this indicator varied from 8.8 % to 16.8 %. At the same time, the lowest values for the protein content were obtained for the variants without the use of fertilizers. In general, the content of protein and gluten in winter wheat grain largely depended on the application of mineral fertilizers and to a small extent on the predecessor. The weight of 1000 grains, depending on these factors, changed insignificantly.

scholarly journals Monomer Release from Resin Based Dental Materials Cured With LED and Halogen Lights

2010 ◽  
Vol 04 (01) ◽  
pp. 034-040 ◽  
Author(s):  
Asli Topaloglu Ak ◽  
A. Riza Alpoz ◽  
Oguz Bayraktar ◽  
Fahinur Ertugrul
Keyword(s):  
High Performance ◽  
Light Emitting Diode ◽  
Dental Materials ◽  
Composite Resins ◽  
Time Intervals ◽  
Significance Level ◽  
Light Emitting ◽  
Quartz Tungsten Halogen ◽  
Bonferroni Test ◽  
One Way Anova

ABSTRACTObjectives: To measure the release of TEGDMA and BisGMA from two commercially available composite resins; Filtek Z 250 (3M ESPE, Germany), Leaddent (Leaddent, Germany) and two fissure sealants; Helioseal F (3M ESPE, Germany) Enamel Loc (Premiere Rev, USA) over 1, 3 and 7 days after polymerization with standard quartz-tungsten halogen Coltolux II (QHL) (Coltene Switzerland) and a standard blue light emitting diode Elipar Freelight 2 (3M ESPE, Germany).Methods: 9 samples of each material were placed in disc shaped specimens in 1 mm of thickness and 10 mm in diameter (n=36). Each material was polymerized using LED for 20 s (n=12), 40 s (n=12) and halogen for 40 s (n=12), respectively. High Performance Liquid Chromatography (HPLC) was used to measure the amount of monomers released over 1, 3 and 7 days. Data was analyzed using one way ANOVA and Bonferroni test for multiple comparisons with a significance level of .05.Results: LED 20 sec group showed the highest release of monomers at 1, 3 and 7 days in sealant groups. Halogen 40 sec group resulted highest release of monomers for Leaddent at all time intervals (P<.05)Conclusions: Efficiency of the curing unit and applying the recommended curing time of the light activated resin based dental materials is very important to protect the patient from potential hazards of residual monomers. (Eur J Dent 2010;4:34-40)

The Relative Importance of Low Significance Level and High Power in Multiple Tests of Significance

1983 ◽  
Vol 56 (2) ◽  
pp. 407-413 ◽  
Author(s):  
Rainer Westermann ◽  
Willi Hager
Keyword(s):  
High Power ◽  
Research Question ◽  
Significance Level ◽  
Tests Of Significance ◽  
Type 1 Error ◽  
Scientific Hypothesis ◽  
Statistical Hypotheses ◽  
Alternative Hypotheses ◽  
Error Probabilities

When several statistical hypotheses are tested in a study to answer a single research question or to test a single scientific hypothesis, interpretation of the results may be difficult because Type 1 error probabilities cumulate. Researchers often try to solve this problem by reducing the significance level for each test or by applying a multiple-comparison procedure for means. For a constant number of observations, both strategies result in a lower power for each test or comparison of interest, however. Two well-known psychological experiments are reanalyzed in this respect. It is shown that low probabilities of Type 1 error should be given a higher priority only if the scientific hypothesis under scrutiny implies that all null hypotheses of the tests of significance are valid. More often, however, the research hypothesis is supported completely if all alternative hypotheses are accepted. In this case, a high power for each single test is more important than a low significance level.

Alliance Behavior in Balance of Power Systems: Applying a Poisson Model to Nineteenth-Century Europe

1975 ◽  
Vol 69 (3) ◽  
pp. 859-870 ◽  
Author(s):  
Patrick J. McGowan ◽  
Robert M. Rood
Keyword(s):  
Power Systems ◽  
International System ◽  
Poisson Model ◽  
Balance Of Power ◽  
Alliance Formation ◽  
Time Intervals ◽  
System A ◽  
Research Questions ◽  
International Systems ◽  
Verbal Model

This paper is a partial systematic test of Morton A. Kaplan's “theory” of alliance behavior in balance of power international systems first proposed in his well-known System and Process in International Politics (1957). Three hypotheses are inferred from Kaplan's writings predicting that in a stable balance of power system, (a) alliances will occur randomly with respect to time; (b) the time intervals between alliances will also be randomly distributed; and (c) a decline in systemic alliance formation rates precedes system changing events, such as general war. We check these hypotheses by applying probability theory, specifically a Poisson model, to the analysis of new data on fifty-five alliances among the five major European powers during the period 1814–1914. Because our research questions are so general, our findings should not be regarded as definitive; however, the data very strongly support our hypotheses. We conclude that Kaplan's verbal model of a balance of power international system has had its credibility enhanced as a result of this paper.

scholarly journals Enhancing Employee’s Capability Maturity Level in Iran’s Oil Company

2019 ◽  
Vol 4 (6) ◽  
Author(s):  
Morteza Raei Dehaghi
Keyword(s):  
Simple Random Sampling ◽  
Face Validity ◽  
Maturity Model ◽  
Maturity Level ◽  
Cross Sectional ◽  
Statistical Population ◽  
Significance Level ◽  
Capability Maturity ◽  
Research Questions ◽  
Oil Company

The present study aimed to explore and evaluate employee’s capability maturity level and propose a solution to enhance it at Iran’s Oil Company. It was conducted through descriptive-field and cross-sectional method. The statistical population included 269 employees who were selected through simple random sampling and the sample size was estimated using Cochran formula. Curtis standard questionnaire was employed for data collection. Face validity and content validity of the questionnaire were confirmed by several experts including the management professors and managers of the mentioned company. Reliability of the questionnaire was confirmed through Cronbach's alpha coefficient which was equal to 0.89. Having analyzed the research questions, the findings revealed that maturity level of employees is totally weak from the third level onward. Therefore, maturity of employees is at the second level of maturity model, i.e. this company has defined and executed its primary and repeatable processes. Likewise, one-sample t-test for each level showed that status of dimensions in the second level was more than the average level (mean was equal to 3.54 and the significance level was less than 0.05) and it was less than the desirable level in other levels (2.69, 2.61, and 2.59 respectively).  

scholarly journals Pengaruh Motivasi Kerja Dan Kompensasi Guru Terhadap Kinerja Guru SMK Swasta Se-Kecamatan Bangil

2019 ◽  
Vol 6 (2) ◽  
pp. 188-192
Author(s):  
Windasari Windasari ◽  
Muchammad Zulham Yahya
Keyword(s):  
High School ◽  
Random Sampling ◽  
Sampling Technique ◽  
Vocational High School ◽  
Validity Test ◽  
Research Results ◽  
Inferential Statistic ◽  
Research Questions ◽  
The Impact ◽  
Cluster Random Sampling

This research objective to find out the impact of motivation and compensation through teachers performance Vocational High School in Bangil district. Collecting data technique used questionnaire and distributed to respondent. Sampling technique is cluster random sampling. Sample for every school are 3 teachers from each major. Totally sample 42 respondents from 5 schools. Validity test used pearson product moment. Analisis technique to answer the research questions are inferential statistic multiple linier regression. Research results showed motivation and compensation have an impact through teachers performance Vocational High School in Bangil District.

scholarly journals Organizations towards the Evaluation of Environmental Management Tools ISO 14001 and EMAS

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4870
Author(s):  
Agnieszka Ociepa-Kubicka ◽  
Iwona Deska ◽  
Ewa Ociepa
Keyword(s):  
Environmental Management ◽  
Economic Incentives ◽  
Iso 14001 ◽  
Management Tools ◽  
Research Results ◽  
Knowledge Based ◽  
Ecological Aspects ◽  
Questions And Answers ◽  
System Functioning ◽  
Research Questions

The purpose of this article is to analyze and compare the benefits of and barriers to the implementation of Environmental Management Systems (EMS)—International Standard ISO 14001 and Eco-Management and Audit Scheme (EMAS)—by organizations. This paper attempts to answer the following research questions: 1. Does the implementation of either ISO 14001 or EMAS bring the same benefits and barriers to organizations? 2. Does the system functioning duration in the company influence internal and external benefits resulting from EMS implementation? 3. Are economic aspects of EMS adoption as important for entrepreneurs as the ecological aspects? This topic is important due to the large disproportions appearing in recent years between the number of companies registered in ISO 14001 and in EMAS, and due to relatively frequent cases of non-renewal of EMAS certifications in recent years. It is crucial because each EMS certified institution has implemented procedures which contribute to better protection of the natural environment. The study was conducted in the form of a survey; questions and answers were specified based on the literature review and the authors’ research. Results indicate that the knowledge-based and organizational problems, as well as the time invested in preparing the documentation, are much more significant than financial problems associated with EMS implementation. Even organizations that previously introduced ISO 14001 still have difficulties with EMAS implementation. The perception of benefits resulting from EMS introduction is related to the system functioning duration in the company. The analysis shows that it is necessary to strengthen economic incentives in order to enable the widest possible dissemination of EMS among companies. Research results can contribute to further simplification and increases in EMS implementation, which may lead to more sustainable development and climate change mitigation, inter alia, due to the improvement in energy efficiency, increased use of renewable energy, and reduction of greenhouse gas emissions.

scholarly journals Investigation of agility performance on 10-12 years soccer players

2015 ◽  
Vol 12 (2) ◽  
pp. 1912 ◽  
Author(s):  
Özcan Saygın ◽  
Kemal Göral ◽  
Halil İbrahim Ceylan ◽  
Sevcan Karacabey
Keyword(s):  
Soccer Players ◽  
Age Group ◽  
Significance Level ◽  
Research Results ◽  
Change Direction

<p>This research was carried out for investigation of 10-12 age soccer players’ agility performance according to age. 53 male soccer players attended in this research voluntarily. Illinois agility test was used in the assessment of agility performance. Collected data was recorded in SPSS program. One Way Variance Analyze (ANOVA)<strong> </strong>was used for determination of differences in different group soccer players. When difference was discerned among groups, Tukey HSD analyses were used for detecting which groups cause this difference. Significance level was accepted as p&lt;0.05. According to research results, significant differences were determined among 10, 11 and 12 age group soccer players’ agility performances (p&lt;0.01). The sources of differences were those, 12 age group soccer players according to 10 and 11 age group showed better performances. Consequently, It can be said that agility feature consisting suddenly stop, change direction and acceleration actions are effected by age in these groups.</p>

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