Preliminary Tests of Normality When Comparing Three Independent Samples

Lantz, Björn; Andersson, Roy; Manfredsson, Peter

doi:10.22237/jmasm/1478002140

Cited by 8 publications

(9 citation statements)

References 23 publications

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“…To define a degree of connection between the percentage decrease in the number of pupils and stated variables in the Federation in the period from 2006 to 2016, the authors used the correlation method. Preliminary analyses for correlation (Rogerson 2001;McCarroll 2016;Pallant 2011) and the results of the Shapiro-Wilk and Kolmogorov-Smirnov tests (Lantz et al 2013) showed p<0.05, as did an analysis using Sperman's correlation coefficient (rho) to determine the degree and direction of relation between the assessed variables.…”

Section: Methodsmentioning

confidence: 99%

Primary-school-age population change in the Federation of Bosnia and Herzegovina: The effects of demographic factors

Kadusic

Smajić

2019

STANOVNISHTVO

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The beginning of the 21st century in the Federation of Bosnia and Herzegovina (henceforth referred to as ?the Federation?) has been characterised by a decrease in the primary-school-age population. As such, the main objective of this work is to define and explain the factors that have influenced the decrease in the primary-school-age population in this part of Bosnia and Herzegovina. The research methodology applied in this work is oriented towards defining the degree of influence of demographic factors on the development of the primary-school-age population in the Federation. By using statistical methods and GIS analysis of statistical data, negative demographic trends were confirmed in the Federation at the end of the 20th and the beginning of the 21st century. These trends included intensive migration, a decrease in the total number of inhabitants, a decrease in the birth rate, an increased mortality rate, a decreased rate of natural population change, and the ageing of the population. Due to adverse economic, social, political, and other circumstances after 1995, population emigration has been intensified, most noticeably within the population aged between 20 and 40. The most important result of the research is the fact that the decrease in the natural population dynamics and intensive emigration are the most significant factors influencing the decrease in the primary-school-age population in the Federation. Such negative demographic trends influence the primary education system adversely. In the future, it will be necessary to plan and implement a population-revitalisation process as part of the federation?s overall population policy.

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Section: Methodsmentioning

confidence: 99%

Primary-school-age population change in the Federation of Bosnia and Herzegovina: The effects of demographic factors

Kadusic

Smajić

2019

STANOVNISHTVO

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“…Levene test was used to judge the homogeneity of variances, while the Shapiro-Wilk normality test was used to assess whether the data met the assumptions of the statistical approach, if the assumptions were not met, Kruskal-Wallis test ANOVA and Conover Multiple Comparison Test for Post hoc were used to demonstrate the significant differences between groups, P-values less than 0.05 were considered significant. (conover, 1999), (Lantz et al, 2016).…”

Section: B-count Of Cfu Of Ementioning

confidence: 99%

Evaluation of Commercial Escherichia Coli Vaccine in Broiler Chickens

MANSOUR¹,

Ibrahim

ALI³

et al. 2023

Assiut Veterinary Medical Journal

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This study is conducted to evaluate the protective effectiveness live-attenuated E.Coli vaccine. A total of 140 broiler chicks were classified into seven groups; the first two groups (1 & 2) were labeled as challenge control for E.Coli O78 and O91 strains, the second two groups (4 & 5) were vaccinated with the E.Coli live-attenuated vaccine at day 1, the third two groups (3 & 6) treated with Difloxacin "second generation fluoro-quinolone" 1ml/L drinking water for first three days of life then vaccinated at day 7 with the E.Coli liveattenuated vaccine. The last group (7) was kept as a control negative group. The challenge was directed to the 21-day-old chicks with either homologous O78 or heterologous O91 E.Coli strains 1.2x10^9 Colony Forming Unit/mL injected intratracheally using 0.5 ml/ bird of each avian pathogenic E.Coli (APEC) strain. Clinical signs, gross and histo-pathological lesions, the intestinal total count of E.Coli (CFU), the chick body weight and the weight of lymphoid organs were calculated at 28 days of age. The results postulated that Poulvac® E.Coli vaccine gives a significant protective effect against the challenge with homologous O78 and the most common heterologous serotype O91. Based on the formentioned parameters, vaccinated birds at 7 days of age (Groups 3&6) which were treated with Difloxacin and challenged with both homologous and heterologous E.Coli serotypes (O78 & O91) showed superior protection over those vaccinated at day one of age (Groups 4&5), challenged with O78 & O91 E.Coli serotypes and did not receive any antibiotic.

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“…In contrast, to estimate the unconditional probability of a Type 1 error given a pre-test for normality, N samples (with mean differ-ence=0) are obtained and each is tested for normality. Samples that pass are subjected to a t-test, samples that do not are subjected to a non-parametric test, then: Lantz et al [32] used simulation to investigate pre-testing of three independent groups design. They used equal sample sizes in each group with three sizes: n=15, n=30 and n=60 per group.…”

Section: Pre-testing For Normality and Variance Heterogeneitymentioning

confidence: 99%

“…Finally, the three simulation studies, [32,45,48], did not explicitly consider the impact of outliers, although a recent paper by Derrick et al [15] identified problems for paired studies with extreme observations. They demonstrated that for small sample sizes a single extreme outlier could reduce the power of the standard t test, even if the outlier is in the same direction as the effect size of the other observations.…”

Section: Pre-testing For Normality and Variance Heterogeneitymentioning

confidence: 99%

Problems with Statistical Practice in Human-Centric Software Engineering Experiments

Kitchenham

Madeyski

Brereton

2019

Proceedings of the Evaluation and Assessment on Software Engineering

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Background Examples of questionable statistical practice, when published in high quality software engineering (SE) journals, may lead to novice researchers adopting incorrect statistical practices. Objective Our goal is to highlight issues contributing to poor statistical practice in human-centric SE experiments. Method We reviewed the statistical analysis practices used in the 13 papers that reported families of human-centric SE experiments and were published in high quality journals. Results Reviewed papers related to 45 experiments and involved a total of 1303 human participants. We searched for issues that were related to questionable statistical practice that were found in more than one paper. We observed three types of bad practice: incorrect use of terminology, incorrect analysis of repeated measures designs, and post-hoc power testing. We also found two analysis practices (i.e., multiple testing and pre-testing for normality) where statisticians disagree about good practice. Conclusions Identified issues pose a problem because readers may expect the statistical methods used in papers published in top quality, peer-reviewed journals to be correct. We explain why the practices are problematic and provide recommendations for improved practice. CCS CONCEPTS • General and reference → Empirical studies; Experimentation; • Software and its engineering → Software creation and management.

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Preliminary Tests of Normality When Comparing Three Independent Samples

Cited by 8 publications

References 23 publications

Primary-school-age population change in the Federation of Bosnia and Herzegovina: The effects of demographic factors

Primary-school-age population change in the Federation of Bosnia and Herzegovina: The effects of demographic factors

Evaluation of Commercial Escherichia Coli Vaccine in Broiler Chickens

Problems with Statistical Practice in Human-Centric Software Engineering Experiments

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