The Normal Distribution and Its Application to Tests of Statistical Significance

2020 ◽  
pp. 267-313
Author(s):  
David Weisburd ◽  
Chester Britt ◽  
David B. Wilson ◽  
Alese Wooditch
Keyword(s):  
Normal Distribution ◽  
Statistical Significance

Hypothesis Probability or Statistical Significance?

Methodology ◽  
2009 ◽  
Vol 5 (1) ◽  
pp. 35-39
Author(s):  
Emilia I. De la Fuente ◽  
Gustavo R. Cañadas ◽  
Joan Guàrdia ◽  
Luis M. Lozano
Keyword(s):  
Normal Distribution ◽  
Statistical Inference ◽  
21St Century ◽  
Statistical Significance ◽  
Research Data ◽  
The Mean

After almost a century of debate among renowned statisticians, 21st century traditional Statistical Inference is marked by controversy over the application of the procedures for hypothesis estimation and contrast. The aim of this paper is twofold: First, to present various debatable issues that arise when the mean in a Normal distribution of known precision is contrasted and second, to argue the suitability of Bayesian philosophy for the analysis of research data.

scholarly journals Analysis of preharvest sprouting in three Brazilian wheat populations

2006 ◽  
Vol 41 (4) ◽  
pp. 583-590 ◽  
Author(s):  
Manoel Carlos Bassoi ◽  
John Flintham ◽  
Carlos Roberto Riede
Keyword(s):  
Normal Distribution ◽  
Seed Coat ◽  
Recombinant Inbred ◽  
Statistical Significance ◽  
Transgressive Segregation ◽  
Preharvest Sprouting ◽  
Wheat Lines

The objective of this work was to evaluate the possibility of obtaining recombinant inbred wheat lines more resistant to preharvest sprouting, independently of colour genes, in three red-grained Brazilian wheat populations. The results showed statistical significance among lines within all populations, which presented a normal distribution and transgressive segregation for preharvest sprouting. The normal distribution of the lines from all red-grained populations suggests that sprouting, excluding the genes expressing seed coat pigmentation, is, probably, controlled by many genes. These findings also indicate that it may be possible to improve resistance to preharvest sprouting, independently of the colour genes.

scholarly journals Evaluation of in-office tooth whitening treatment with violet LED: protocol for a randomised controlled clinical trial

BMJ Open ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. e021414 ◽  
Author(s):  
Ana Eliza Castanho Garrini dos Santos ◽  
Sandra Kalil Bussadori ◽  
Marcelo Mendes Pinto ◽  
Dácio Antonio Pantano Junior ◽  
Aldo Brugnera Jr ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Normal Distribution ◽  
Analysis Of Variance ◽  
Repeated Measures ◽  
Statistical Significance ◽  
Wilcoxon Test ◽  
Controlled Clinical Trial ◽  
Tooth Whitening ◽  
Randomised Controlled Clinical Trial ◽  
Randomised Controlled

IntroductionIn-office tooth whitening treatment using violet light emited diode (LED) (405 nm) is a novel bleaching method that causes less sensitivity while offering the same effectiveness as the gold standard (35% hydrogen peroxide, H2O2). This study describes a protocol for the first randomised controlled clinical trial to compare the effects of the two methods.Methods and analysisEighty patients will be divided into four groups: G1 violet LED; G2 violet LED +35% carbamide peroxide; G3 35% H2O2and G4 violet LED +gingivoplasty. Colour will be measured at baseline, immediately after the first session and at the 15 and 180 days follow-up using the Vita Classical and the digital Easyshade V spectrophotometer (Vita, Zahnfabrik, Germany). Sensitivity after whitening will be measured using the Visual Analogue Scale at baseline and at each session in all groups and in all follow-ups. The tissue removed during gingivoplasty (G4) will be submitted to immunohistochemical analysis for the determination of inflammatory changes caused by violet LED. The Psychosocial Impact of Dental Aesthetics Questionnaire (PIDAQ) will be evaluated before, as well as at established time point controls. The results will be expressed as mean and SD values. After determining the normality of the data, a one-way repeated-measures analysis of variance will be used for the comparison of data with normal distribution and the Kruskal-Wallis test will be used for data with non-normal distribution. A p<0.05 will be considered indicative of statistical significance. After determining the normality of the data, the Kruskal-Wallis test will be used for non-parametric data. Multivariate analysis of variance (MANOVA) and the Wilcoxon test will be used for comparing data from the PIDAQ.Ethics and disseminationThis protocol has been approved by the Human Research Ethics Committee of UniversidadeNove de Julho (certificate: 2.034.518). The findings will be published in a peer-reviewed journal.Trial registration numberNCT03192852; Pre-results.

Comparison of Parametric and Non-Parametric Methods to Analyse the Data Gathered by a Likert-Type Scale

2021 ◽  
pp. 414-430
Author(s):  
Tamer Baran
Keyword(s):  
Normal Distribution ◽  
Statistical Significance ◽  
Rank Test ◽  
Response Alternative ◽  
Parametric Methods ◽  
Signed Rank Test ◽  
Response Alternatives ◽  
The One ◽  
Different Response ◽  
Non Parametric

The aim of this chapter is to reveal whether the results of the analysis of the data obtained using Likert type scales (LTSs) with parametric and non-parametric methods in different response alternative (DRA) numbers will differ in terms of statistical significance. In this respect, the data were obtained from 271 university students with CETSCALE prepared using LTS in five different response alternatives (DRAs). The data were analysed using the one sample t test and Wilcoxon signed rank test. Significant findings of the study in the analysis of the data obtained using midpoint LTSs and with the normal distribution with both parametric and non-parametric methods couldn't be found. Similarly, the data obtained by four response alternative numbers with the normal distribution were analysed by both methods, and the significant findings were revealed. However, the results of the data obtained by six and eight response alternative numbers with parametric methods were found to be statistically significant while their analysis by non-parametric methods did not reveal significant findings.

Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

1991 ◽  
Vol 49 ◽  
pp. 376-377 ◽  
Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay
Keyword(s):  
Surface Charge ◽  
Environmental Effects ◽  
Scanning Probe Microscopy ◽  
Statistical Significance ◽  
Electrochemical Methods ◽  
Surface Structures ◽  
Scanning Probe ◽  
Potential Control ◽  
Afm Imaging ◽  
Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

Influence of Maternal Education on Food Consumption and Energy and Nutrient Intake in a Group of Pre-School Children from Madrid

2003 ◽  
Vol 73 (6) ◽  
pp. 439-445 ◽  
Author(s):  
Navia ◽  
Ortega ◽  
Requejo ◽  
Perea ◽  
López-Sobaler ◽  
...  
Keyword(s):  
Food Consumption ◽  
School Children ◽  
Food Habits ◽  
Nutrient Intake ◽  
Maternal Education ◽  
Statistical Significance ◽  
Dietary Adequacy ◽  
Consumption Energy ◽  
Maternal Educational Level ◽  
Energy And Nutrient Intake

A study was conducted on the influence of maternal education level on food consumption, energy and nutrient intake, and dietary adequacy in 110 pre-school children from Madrid, Spain. With increasing maternal education, children consumed more sugar (p < 0.05), fruit (p < 0.05), and fish (p < 0.05). Snacking was more frequent with decreasing maternal education (p < 0.05). Though statistical significance was not reached, the consumption of pre-cooked foods was greater among children of mothers educated to a higher level, a phenomenon probably related to the work situation of these women. With respect to dietary composition, no significant differences were found between groups for macronutrient, fiber and energy intakes, except for energy supplied by polyunsaturated fatty acids (PUFA), which was greater in the children of less educated women (p < 0.01). This is probably due to their greater consumption of sunflower seed oil. The diets of children belonging to well-educated mothers came closer to meeting the recommended intakes for folate, vitamin C, and iodine. It would seem that maternal educational level influences the food habits of children. Mothers with less education may require special advice in this area.

Use of vascular closure devices for endovascular interventions requiring a direct puncture of PETE grafts

VASA ◽  
2018 ◽  
Vol 47 (2) ◽  
pp. 119-124 ◽  
Author(s):  
Artur I. Milnerowicz ◽  
Aleksandra A. Milnerowicz ◽  
Marcin Protasiewicz ◽  
Wiktor Kuliczkowski
Keyword(s):  
Statistical Significance ◽  
Vascular Complications ◽  
Vascular Complication ◽  
Inguinal Region ◽  
Closure Device ◽  
Manual Compression ◽  
Direct Puncture ◽  
Endovascular Interventions ◽  
Vascular Closure Devices ◽  
Closure Group

Abstract. Background: Effectiveness of vascular closure devices during endovascular procedures requiring a direct puncture of a vascular prosthesis placed in the inguinal region is unknown. Patients and methods: The retrospective analysis included 134 patients with a history of polyethylene terephthalate (PETE) graft implantation in the inguinal region. In 20 (15 %) patients, haemostasis was achieved with manual compression, in 21 (16 %) with the StarClose™, and in 93 (69 %) with the AngioSeal™ device. Results: The incidence of vascular complications in the manual compression group was higher (at a threshold of statistical significance) than in the device closure group (45.0 vs. 24.5 %, p = 0.059). The difference was considered statistically significant when manual compression was compared with the AngioSeal™ closure group (45.0 vs. 13.9 %, p < 0.01). The vascular complication rate in the StarClose™ group was significantly higher than in the AngioSeal™ group (71.4 vs. 13.9 %, p < 0.000001). While haematomas were the only vascular complications observed after application of AngioSeal™, both haematomas and pseudoaneurysms were found in the StarClose™ group. Conclusions: The AngioSeal™ vascular closure device provides better local haemostasis than the StarClose™ device or manual compression during endovascular interventions requiring a direct puncture of PETE grafts

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